3D view: now displays polygons used in footprint shapes, like logos. Fixed very minor issues (minor warnings in debug mode)

3D export: Added patch from Lorenzo Marcantonio. Fixed issue in VRML export dialog.  Removed useless messages in debug mode.

Fixed compil warning under wxWidgets 2.9.1.
File beautification
Statring using wxTextEntryDialog instead of Get_Message (because Get_Message does not handle properly cancel option)

inches and mm, the industry is crazy enough to force us with mixed
design. For example I routinely use imperial units for track size and
clearance, but drilling is strictly a metric issue...

So I added a little parser to recognize a suffix specification in the
unit text boxes... so you can put in things like:
1in (1 inch)
1" (idem)
25th (25 thou)
25mi (25 mils, the same)
6mm (6 mm, obviously)

The rules are: spaces between the number and the unit are accepted, only
the first two letters are significant.

As a bonus, it also recognize the period (.) as a decimal point
substituting it with the correct locale character (there was a wishlist
for it, IIRC). Most useful for number pad fans :D 

preparing auto refresh of the 3D view in mod edit (not yet working)

* Implement code to allow wxDC to handle coordinate conversions between
  device and drawing units.
* Add build settings to enable wxGCDC for wxGraphicsContext testing.
* Remove wxAUI conditional build cruft as it is now required to build
  Kicad.
* Fix scroll increment size regression to prevent jumping around the
  zoom center position.
* Add find GDI+ cmake module for building on WXMSW when wxGraphicsContext
  is enabled.

removed global variables and a lot of redundancies

hide/show rastnest in pcbnew is currently not working, will be fixed soon

Better code in fast draw grid algo (drawpanel.cpp):must be faster, and minor refresh problems removed under wxGTK

Code cleaning.
Patch for 3D problem with macOSX

  * Moved ReturnLayerName() to static BOARD::GetDefaultLayerName() and migrated
    to a Specctra DSN compatible default layer naming scheme:
        Component becomes Front, Copper becomes Back.
  * set_color.h: Cmp becomes Front, Cu becomes Back.
  * D_PAD::DisplayInfo() changed to use actual copper layer names.
  * more layer setup dialog work, moved all programmatic wxControl instantiation
    into the wxFormbuilder environment, but this is fraught with danger:
    wxFlexGridSizer used the tallest control to establish the row heights, so
    be careful about changing control borders in the scroll panel. The vertical
    size can explode since just a couple of pixels times the number of rows
    is substantial.  Currently I am setting a 5 pixel border only left, top, and right
    but not bottom.
  * Set copper layer count is back in place as a hack until I can get the enabled
    layer bit map fully operational.

* Complete comment translation for all EESchema source files.
* Complete comment translation for all 3D viewer source files.
* Rename class class_hierarchical_PIN_sheet to SCH_SHEET_PIN.
* Rename class DrawSheetStruct to SCH_SHEET.
* Tool tip capitalization fixes.
* Uncrustify and spell check comments and strings in all modified source
  files.

* Split out application specific command IDs to prevent unnecessary rebuilding.
* Eliminate duplicate menu and tool bar command IDs.
* Split component library editor and viewer definitions to separate header files.
* More component library and document file merge code.
* A bunch of minor string readability and consistency fixes.

enhancement in Cvpcb: fast selection of components or footprint by typing the first letter of reference or footprint name

better compatibility with wxWidgets 2.9. Markers enhancement in pcbnew (right click can display marker info)

3D view: fixed: mirrored texts incorrectly drawn

Minor others changes.