- SEGVIA becomes VIA
- Drill size moved from TRACK to VIA
- Removed shape from TRACK, becomes ViaType in VIA
- GetTrace becomes GetTrack, for uniformity
- Some minor constification and typo fixes

!   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.

Added KiCad-style modification methods (hover over an item and press a hot key, without selecting first).
Modification point is selected basing on the number of selected items.
Rotation angle setting (Preferences->General) is taken into account while rotating.

- pcbnew.InteractiveSelection.Single for selecting a single item
- pcbnew.InteractiveSelection.Clear for clearing the selection
Made SELECTION_TOOL::clearSelection private.

SELECTION_TOOL::SELECTION::Clear made private, as there was no chance to call it outside the SELECTION_TOOL class.

Fixed crashes of ratsnest when a pointer for an item has changed after undo/redo operations.
Vias are properly removed from ratsnest (pcbnew/class_board.cpp).

RN_DATA::Update()/AddSimple() take BOARD_ITEM* as the parameter (instead of being split to versions with BOARD_CONNECTED_ITEM* and MODULE*), to make the code look clearer.

Removed debug output.

Modifications done using the EDIT_TOOL are saved using the default KiCad's undo buffer.
If there is only one item selected, info about the item is displayed in the bottom status bar.

Added REASON enum for Reset() function, so tools will know why a reset occured.
Fixed SELECTION_TOOL (it was bailing out, when a new board was loaded and some items were still selected).
Added removal of VIEW_ITEM groups after changing layers and removing items.

Changed selection rules (pads&modules can be selected depending on the 'modules front/back' visibility instead of corresponding copper layers).
Fixed comments.

Added Properties action (display properties windows)