Fix minor bug #1429990 (3D viewer shows hidden footprint graphic texts ). Fix minor coverity warnings (not initialized members and dead code)

Eeschema now uses dashed lines for graphic lines (to be consistent with plot functions and toolbal icon).
Fix an old bug in some envionments which warp the mouse on a bad monitor when opening eeschema, pcbnew and some other windows, only noticeable guys who are lucky enough to have more than one monitor.

Fix some coverity warnings (not initialized members). Add comments. Better (more informative) title in dialog to download .pretty libs.

Pcbnew: fix  Bug #1422093 (pcbnew crashes after editing a footprint cominng from the board  with the fp editor and saving it on a librray and trying to load it to the board)
Some other very minor fixes.

Pcbnew: fix Bug #1413701 (Segfault on highlight "unconnected" net 0 in Pcbnew ). Also, remove now useless code and other very minor fixes.

Minor and very minors fixes: move -DKICAD_USE_WEBKIT definition to the main CMakeLists.txt. Remove duplicate semi-colon at end of some lines.

Fix issue when using a page layout file in project folder: eeschema and Pcbnew did not use it, unless using an absolute path.
Now, if the file path is nor absolute, it is seen as relative to the project (which is the expected behavior)
fp lib wizard: when pcbnew id compiled with USE_GITHUB_PLUGIN=OFF, the github plugin option is no more accessible (and the web viewer no more used).

BOM dialog: remove a not very useful button, and merge its function with an other (not perfect, need more work)
Add message box to show info added in BOM python scripts (See scripts/bom-in-python/README-bom.txt about this info)

Grebview: add info in layer manager for Excellon drill filles, similar to X2 file function info in X2 gerber files.

Gerbview: Add support for recent File Format Attribute metadata, both for X2 Gerber file format and X1 (R274X) format.
Pcbnew already uses this attribute when creating Gerber files.
Because Gerber files using this attribute identify the board layers stackup, Gerbview (if this attribute is defined) can sort gerber images stach up like the board.
(in layer manager, just right click to access to the sort menu)

* Make title capitalization consistant.
* Replace some instances of module with footprint.
* Use angle instead of orientation where appropriate.
* Remove abbreviations where it made sense.
* Coding policy fixes.

  steps to better support devices with precise scrolling deltas (trackpads).
  Scrolling is done in the handler rather than creating and firing cmd events.
  This is intended to support two-finger scrolling on the Magic Trackpad.
- Added a preference, 'Use mousewheel to pan', to allow panning by default
  on mousewheel events.  This reverses the existing behavior where unmodified 
  mousewheel zooms and Shift/Cmd modified pans.  

  The old behavior was:
  - Unmodified scrollwheel performed zoom in/out
  - Shift modified scrollwheel performed pan up/down
  - Cmd modified scrollwheel performed pan left/right
  - Shift+Cmd modified scrollwheel performed zoom in/out
    with no cursor warp

  With the new preference checked, this changes to:

  - Unmodified scrollwheel performs pan up/down
  - Shift modified scrollwheel performs pan left/right
  - Cmd modified scrollwheel performs zoom in/out
  - Shift+Cmd modified scrollwheel performs zoom in/out
    with no cursor warp

  With the preference unchecked, this is now:
  - Unmodified scrollwheel performed zoom in/out
  - Shift modified scrollwheel performed pan left/right
  - Cmd modified scrollwheel performed pan up/down
  - Shift+Cmd modified scrollwheel performed zoom in/out
    with no cursor warp

  It should be noted that for the last case, the behavior has changed.
  This is not arbitrary.  This now matches expected behavior for an OS X
  application.  This also matches what wxWidgets expects on this platform
  as wxWidgets changes the axis of mousewheel events to horizontal when
  the event is shift-modified.

  The preference is added everwhere that mouse preferences previously
  existed, i.e., eeschema, pcbnew and gerbview.  The 3D Viewer does
  not yet honor this preference, but behaves as if it was checked.
  The pl_editor does not currently have any preferences to honor.

  As with the magnify event support, this covers canvases for all
  current tools, EDA_DRAW_PANEL, EDA_3D_CANVAS and EDA_DRAW_PANEL_GAL.

  This does NOT modify the behavior of mousewheel zooming, though it
  probably should.  This remains unsuitable for use with a trackpad,
  use pinch-to-zoom instead.

* Fix creation of single app bundle with respect to scripting support.
* Cleanup scripting search paths for OSX.
* Fix some small CMake bugs from previous OSX build change.
* Optimize bundle file structure to be consistent with Apple specs.
* Add helper script for compiling wxWidgets and wxPython
* Update OSX build instructions.

* Remove obsolete settings from Doxygen configuration file.
* Fix some Doxygen warnings.
* Add the board edge segment snapping to developers road map.
* Fix some coding style issues in CMakeLists.txt

* Compile all binaries into a single application bundle.
* Use CMake BundleUtilities to make application bundle relocatable.
* Restructure build output to directly create an image file.
* Fix default search paths.
* Set KIGITHUB environment variable.
* Added patch to fix wxWidgets so names for OSX.

* Add hot key handled return indicator to DRAW_FRAME::GeneralControl() and
  DRAW_FRAME::OnHotKey() and all classed derived from DRAW_FRAME.
* Add code to all GeneralControl() and OnHotKey() functions to return true if
  hot key was handled.
* Call event skip in DRAW_PANEL::OnKeyEvent() when key event is not handled to
  allow default menu event handler to function properly.

  *) When kicad.exe closes a project, close any open KIFACEs so that they cannot
     get disassociated from their true PROJECT.
  *) Allow loading eeschema library editor from kicad.exe
  *) Allow loading pcbnew library editor from kicad.exe
  *) Rename LIB_COMPONENT to LIB_PART.
  *) Add class PART_LIBS, and PART_LIB.
  *) Make PART_LIBS non-global, i.e. PROJECT specific.
  *) Implement "data on demand" for PART_LIBS
  *) Implement "data on demand" for schematic SEARCH_STACK.
  *) Use RSTRINGs to retain eeschema editor's notion of last library and part being edited.
  *) Get rid of library search on every SCH_COMPONENT::Draw() call, instead use
     a weak pointer.
  *) Remove all chdir() calls so projects don't need to be CWD.
  *) Romove APPEND support from OpenProjectFiles().
  *) Make OpenProjectFiles() robust, even for creating new projects.
  *) Load EESCHEMA colors in the KIWAY::OnKiwayStart() rather in window open,
     and save them in the .eeschema config file, not in the project file.
  *) Fix bug with wxDir() while accessing protected dirs in kicad.exe
  *) Consolidate template copying into PROJECT class, not in kicad.exe source.
  *) Generally untangle eeschema, making its libraries not global but rather
     held in the PROJECT.

Fix crash in Pcbnew and Gerbview when seceting (in layers manager) "always hide all layers but activer"

Better separation between Pcbnew code and Gerber code.
Update export to Pcb code (uses now the version 4  kicad_pcb file format).

Gerbview: allows x.7 format (recently indroduced in Gerber format)
Also minor coding style fixes.

Gerbview: allows x.7 format (recently indroduced in Gerber format)
Also minor coding style fixes.

Gerber output: Some changes after evaluation of Gerber files by Ucamco (the manager of GERBER format):
* default file ext is now .gbr (the "official extension")
* some outdated commands remoded.
* mainly use mm and 4.5 format instead of inches and 3.4 format. this is mandatory,
  because the 3.4 format (comming from old pcbned internal units) creates truncations in coordinates.
  (with serious issues in polygons which can appear self-intersecting afer truncation)

Export to Pcbnew is broken, but it is a very rarely used feature. It will be fixed later.

2) Change from legacy Cu stack to counting down from top=(F_Cu or 0).
   The old Cu stack required knowing the count of Cu layers to make
   sense of the layer number when converting to many exported file types.
   The new Cu stack is more commonly used, although ours still gives
   B_Cu a fixed number.
3) Introduce class LSET and enum LAYER_ID.
4) Change *.kicad_pcb file format version to 4 from 3.
5) Change fixed names Inner1_Cu-Inner14_Cu to In1_Cu-In30_Cu and their
   meanings are typically flipped.
6) Moved the #define LAYER_N_* stuff into legacy_plugin.cpp where they
   can die a quiet death, and switch to enum LAYER_ID symbols throughout.
7) Removed the LEGACY_PLUGIN::Save() and FootprintSave() functions.
   You will need to convert to the format immediately, *.kicad_pcb and
   *.kicad_mod (=pretty) since legacy format was never going to know
   about 32 Cu layers and additional technical layers and the reversed Cu
   stack.

They are now member of EDA_DRAW_FRAME.
This change could fix Bug #1330781 (Background color change in Eeschema affects background color in Pcbnew)
Show page limits has meaning only for the schematic editor,  the board editor and the page layout editor.
Draw background color selection exists only in eeschema and  page layout editor.
In pcbnew, only a black background is allowed.
A side effect is now the user should set the background color in schematic editor, and the library editor (2 different options).
The default is still the white color.

- Refactored the common part of cursor key movement and crosshair update
  in the various GeneralControl
- Add x10 movement with the keyboard (CTRL modifier)
- Avoid fixup of the cursor position by dummy mouse movements generated
  by cursor warping (original analysis and idea Chris Gibson)
- Do key handling in a way to permit sub-pixel cursor movement