CMake: add definition KICAD_TESTING_VERSION and KICAD_STABLE_VERSION.
One of these 2 options *must* be now defined (i.e. run cmake with option -DKICAD_STABLE_VERSION or -DKICAD_TESTING_VERSION
Stable and testing branches should be more easier to maintain.

All: fix a very minor issue: when a window is closed mazimized, and later reopened, it was not maximized.

fix an issue created by commit 2954. Gerbview: display now an indicator of layers in use. minor code cleanup.

* Move undo item copy global variable into schematic editor frame object
  member variable.
* Add helper methods for accessing the undo item copy member variable.
* Fix undetected bug when changing a text type.
* Added an exchange command to the undo/redo base class for handling undoing
  a changed item type which cannot be undone by swapping out the variables.
* Revert change to common/hotkeys_basic.cpp that broke hot key behavior.
* Lots of coding policy changes while making the changes above.

* store selected language by name instead of wx language id (that changes between wxWidgets version)
* accept always comma and point as flotating point separator.

* Rename EDA_Rect class to EDA_RECT.
* Rename EDA_TextStruct class to EDA_TEXT.
* Remove duplicate Doxygen comments from sch_sheet_path.cpp.

fix 2 minor bugs: GERBVIEW: Button "Erase all layers" not working, EESCHEMA: Plot to Clipboard: EDA_DRAW_FRAME::PrintPage() error

* Fix about dialog escape key termination bug.
* Fix edit hot keys dialog escape key termination bug.
* Set schematic editor component properties dialog default button.
* Fix schematic editor plot DXF dialog escape key termination bug.
* Set PCB editor layers setup dialog default button.
* Set PCB editor swap layers dialog default button.
* Set PCB editor net list dialog default button.
* Add comment to UIPolicy.txt about escape key termination requiring proper
  dialog button IDs.

* Set default button on all dialogs that do not already have a defined
  default button.  The only exception is the EESchema net list dialog
  which needs converted over to wxFormBuilder and due to it's design makes
  setting the default button in any tab other than the default tab
  problematic.
* Fix escape key dialog handling bug in EESchema print post script
  dialog.

others: fix minor issues.

* Remove clearance and net class name read only text boxes from PCBNew
  auxiliary tool bar.
* Display full net class information in message panel when an object that
  supports net classes is selected.
* Move coordinate string conversion function to EDA_DRAW_FRAME object and
  made it more versatile.
* Refresh message panel text when units change.

Pcbnew: dialog plot: make message window resizable, add tool tip and remove unused sizers.

* Move locate function code into schematic screen object.
* Move test for junction needed into schematic screen object.
* Move test for marking connected items into schematic screen object.
* Move delete item function code into schematic screen object.
* Move delete all markers code into schematic screen object.
* Add method for locating multiple items in schematic screen object.
* Fix minor bug in schematic field object hit test declaration.
* Initial encapsulation work on item picker object.
* Remove duplicate doxygen comments from item picker object source file.

All: fix a minor bur annoying issue: incorrect cursor shape after a block command (mainly when a tool is selected)

* Fix grid select box update bug on context menu.
* Fix via size and track width select box update bugs.
* Fix layer pair indicator button update bug.
* Fix auto track width tool bar control enable bug.
* Fix via size and track width select status bug in context menu.
* Fix layer select box and layer control widget select bug when current
  layer is removed.
* Add virtual function to notify objects derived from EDA_DRAW_FRAME that
  the units setting has changed.
* Coding policy class naming fixes.

Eeschema, Pcbnew: fix minor issues about mouse cursor position, when loading files or entering sheets.

Use UTF-8 encoding only in kicad files. Under Linux, this was already the case. Under Windows, texts with  non ascii characters must be corrected.
This ensure compatibility between platforms.

* fix incorrect bounding box size calculation of schematic components.
* fix incorrect bounding box position and size used when schematic components are not found in lib (dummy lib componen used).
Pcbnew:
* Fix issues in block selection for arcs in modedit. Minor code cleaning.
CopyToClipboard: fix incorrect call to PrintPage (bad parameters)

kicad: fix Russian GOST page reference sheet - add field 24-25

* Make EDA_DRAW_FRAME current tool ID member variable private.
* Added global no tool selected ID to replace application specific no
  tool selected IDs.
* Change SetToolID to prevent setting the tool ID to anything less than
  the new global no tool selected ID and assert on debug builds.
* Change command and update user interface command event handlers to use
  new global no tool selected ID.
* Fixed schematic library editor add pin hot key handler.