(for instance, when a footprint from the currently edited board is loaded in the footprint editor, and when the board is cleared or reloaded)
In footprint editor, the net names are no more shown od modifiable (becuase the footprint editor does not know anything about net names.
This change should allow the changes planned in pcbnew.

!   The initial testing of this commit should be done using a Debug build so that
    all the wxASSERT()s are enabled.  Also, be sure and keep enabled the
    USE_KIWAY_DLLs option.  The tree won't likely build without it.  Turning it
    off is senseless anyways.  If you want stable code, go back to a prior version,
    the one tagged with "stable".

*   Relocate all functionality out of the wxApp derivative into more finely
    targeted purposes:
    a) DLL/DSO specific
    b) PROJECT specific
    c) EXE or process specific
    d) configuration file specific data
    e) configuration file manipulations functions.

    All of this functionality was blended into an extremely large wxApp derivative
    and that was incompatible with the desire to support multiple concurrently
    loaded DLL/DSO's ("KIFACE")s and multiple concurrently open projects.
    An amazing amount of organization come from simply sorting each bit of
    functionality into the proper box.

*   Switch to wxConfigBase from wxConfig everywhere except instantiation.
*   Add classes KIWAY, KIFACE, KIFACE_I, SEARCH_STACK, PGM_BASE, PGM_KICAD,
    PGM_SINGLE_TOP,
*   Remove "Return" prefix on many function names.
*   Remove obvious comments from CMakeLists.txt files, and from else() and endif()s.
*   Fix building boost for use in a DSO on linux.
*   Remove some of the assumptions in the CMakeLists.txt files that windows had
    to be the host platform when building windows binaries.
*   Reduce the number of wxStrings being constructed at program load time via
    static construction.
*   Pass wxConfigBase* to all SaveSettings() and LoadSettings() functions so that
    these functions are useful even when the wxConfigBase comes from another
    source, as is the case in the KICAD_MANAGER_FRAME.
*   Move the setting of the KIPRJMOD environment variable into class PROJECT,
    so that it can be moved into a project variable soon, and out of FP_LIB_TABLE.
*   Add the KIWAY_PLAYER which is associated with a particular PROJECT, and all
    its child wxFrames and wxDialogs now have a Kiway() member function which
    returns a KIWAY& that that window tree branch is in support of.  This is like
    wxWindows DNA in that child windows get this member with proper value at time
    of construction.
*   Anticipate some of the needs for milestones B) and C) and make code
    adjustments now in an effort to reduce work in those milestones.
*   No testing has been done for python scripting, since milestone C) has that
    being largely reworked and re-thought-out.

Pad editor dialog: Better tests and error messages about issues in pad settings. Fis also an other hard to translate error messge.

Footprint Editor: fix a crash when the dialog to set pad properties is called from the main toolbar (i.e. to define the default setting for new pads, and not to edit an existing pad)

Renamed BOARD_CONNECTED_ITEM::SetNet() -> SetNetCode()
Added BOARD_CONNECTED_ITEM::GetNet() for accessing NETINFO_ITEM* of a given item.
Fixed module editor crash when launched to edit a module from a PCB.
Replaced some BOARD::FindNet( item->GetNet() ) calls with BOARD_CONNECTED_ITEM::GetNet().

Renamed BOARD_CONNECTED_ITEM::SetNet() -> SetNetCode()
Added BOARD_CONNECTED_ITEM::GetNet() for accessing NETINFO_ITEM* of a given item.
Fixed module editor crash when launched to edit a module from a PCB.
Replaced some BOARD::FindNet( item->GetNet() ) calls with BOARD_CONNECTED_ITEM::GetNet().

Pcbnew: fix bug #1272714 . Code cleanup: use 2 different enums for pad shapes and pad drill shapes. Remove never used pad shape.

D_PAD::GetNetname() and D_PAD::GetShortNetname() were moved to BOARD_CONNECTED_ITEM. Now they use the net name stored in NETINFO_ITEM.
Moved some one-line functions from class_board_connected_item.cpp to class_board_connected_item.h.
Added a copyright notice, moved Doxygen comments from class_board_connected_item.cpp to class_board_connected_item.h.

I have some doubts if changes introduced pcbnew/dialogs/dialog_pad_properties.cpp do not break anything, but I could not find a test case that breaks the pcbnew.

Performed tests:
- changed pad's net name from empty to existent - ok, name was changed
- changed pad's net name from empty to nonexistent - ok, error message is displayed, net name stays empty
- changed pad's net name from existent to empty - ok, net name became empty
- changed pad's net name from existent to nonexistent - ok, error message is displayed, net name is not changed
- (re)reading netlists, including net changes - fine, changes are applied, but empty nets are still kept
- loaded pcbnew/pcad2kicadpcb_plugin/examples/CK1202_V1.pcb to test P-CAD import plugin - ok, net names are correct
- imported an Eagle 6.0 board (Arduino Uno; http://arduino.cc/en/uploads/Main/arduino_Uno_Rev3-02-TH.zip) then saved in .kicad_pcb format and reloaded - ok, net names are correct
- saved demos/video/video.kicad_pcb in legacy format and then loaded it again - ok, net names are correct

Pcbnew: Fix Bug #1185556. fix issue about Solder Paste Ratio value which was accepting only one digit in mantissa in 3  dialogs  (now 6 digits in all dialogs).
fix potential issue in .kicad_pcb file creation, in some places where a %g or %.16g format was used:
al least under Mingw/gcc4.7.2, the floating number was written using scientific notation, not accepted by the S-expr reader.

- Removed spurious int casts (these are truncated anyway and will break
  doubles)

- Applied the Distance, GetLineLength, EuclideanNorm, DEG2RAD, RAD2DEG
  ArcTangente and NORMALIZE* functions where possible

- ArcTangente now returns double and handles the 0,0 case like atan2, so
  it's no longer necessary to check for it before calling

- Small functions in trigo moved as inline

* Create separate NETLIST object to hold contents of netlist files.
* Read entire netlist and footprint link files before making applying
  changes to board.
* Add BOARD::ReplaceNetlist() function to eliminate the calls between the
  NETLIST_READER, PCB_EDIT_FRAME, and BOARD objects.
* Change placement of new components below the center of the current board
  or in the center of the page if the BOARD is empty.
* Add dry run option to netlist dialog to print changes to message control
  without making changes.
* Add button to netlist dialog to allow saving contents of message control
  to a file.
* Eliminate the need to compile netlist_reader_*.cpp in both CvPcb and Pcbnew.
* Add netlist_reader_*.cpp to the pcbcommon library.
* Remove redundant load component link file code from CvPcb.
* Modify CvPcb new to work with the new NETLIST_READER object.
* Add compare() function and < and == operators to FPID object.
* Add REPORTER class to hide an underlying string writing implementation for
  use in low level objects.  Thank you Dick for the idea.
* Lots of minor coding policy, Doxygen comment, and missing license fixes.

- Renamed ReturnMaskLayer to GetLayerMask (since it's a plain getter)

* Fixed spacing issue in pad properties dialog.
* Remove wxSHAPED flag from pad drawing panel to prevent assertion in
  wxSizer.
* Used sane default pad size and drill size settings to prevent wxRound
  assertions.
* Add license to class_board_design_settings.cpp.

* Improve MSG_PANEL_ITEM to handle message panel information.
* Create containers for passing message panel items between objects and
  the message panel.
* Rename EDA_ITEM::DisplayInfo to EDA_ITEM::GetMsgPanelInfo.
* Remove all direct manipulation of EDA_DRAW_FRAME from all objects derived
  from EDA_ITEM.

Try to fix an unwanted left mouse release button event, when closing a dialog on a click or double click,
and therefore when the mouse butoon is released in the parent window
Minor other fixes.

All: remove macros  MAX, MIN, ABS from macros.h and replace these macros by std::max, std::min and std::abs (mainly found in old code).

All: fix a truncation issue in ReturnValueFromString that creates sometimes a small error for values entered in dialogs.
Pcbnew: fix a compatibility issue with nano version for zones parameters.

Because this bug could create bad values in footprint libraries, this parameter is now checked
when reading a footprint description in legacy format

* Move all convert from user to internal units into base_units.cpp.
* Remove internal units parameters from all moved conversion functions.
* Revise all source code that calls the moved conversion functions.
* Remove internal units from all dialog text control helper classes.

* Move all convert from internal to user units functions into separate file.
* Remove internal units parameter from all moved conversion functions.
* Revise all source code that calls the moved conversion functions.
* Compile these conversion routines separately for the appropriate pcb or
  schematic internal units.
* Move internal units specific status bar update code into the appropriate
  application for updating the status bar.
* Move millimeter user units rounding function to common.cpp.

* Fix bug in PCBNEW dialog_pad_properties.cpp that I introduced several days ago.
  The m_Master_Pad stuff is stored in the PCB_EDIT_FRAME's BOARD_DESIGN_SETTINGS,
  not in the FOOTPRINT_EDIT_FRAME's BOARD_DESIGN_SETTINGS (i.e. not stored in 
  the module editor's dummy BOARD).  Now we properly initialize the
  DIALOG_PAD_PROPERTIES::m_Pad_Master reference to the correct master pad
  dope, instead of to the dummy module BOARD's master pad, which is not used.

class EDA_RECT: is no more derived from EDA_ITEM, just from EDA_RECT (reason: does not use anything in EDA_ITEM)
issue in cast to wxRect fixed (EDA_RECT accepts negative size, but not wxRect, so the wxRectcast  is normalized now).
This fixes some bugs.
A minor other bug fix in Pcbnew.

subclass DIALOG_SHIM support.
Tried dialog_drc but it has nesting problems due to use of DRCLISTBOX, which
needs to be put into its own header file to untangle.

Ckecks more pad parameters in pad editor dialog (previously not tested, so a pad could have some very incorrect parameters)