Pcbnew: fix bug  #142348 (airwire does not always appear after deleting a track). Very minor other fixes.

* Fix coverity scan error for array comparison.
* Check for buffer length overflow that fixes segfault.

* Add support for setting python site package path to PYTHON_SITE_PACKAGE_PATH.
* Move configure_file() so WXPYTHON_VERSION is already initialized before creating
  config.h (Duh!).
* Add status message to indicate the version of wxPython found.

Temporary fix a crash I created in rev 5427, when erasing all modules on a board and read the netlist. Will be fully fixed later.
Very minor fixes: remove duplicate #define in vrml_v2_modelparser.cpp, and "undo" a very minor change I made in class_board.cpp when I tried to fix a Pcbnew crash.

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.

* Fix resource leak in idf_parser.cpp
* Fix logically dead code in idf_parser.cpp
* Fix use after free bug in idf_parser.cpp
* Fix unitialized scalar value in idf_parser.cpp
* Fix logically dead code in idf_outlines.cpp
* Fix unitialized scalar value in idf_outlines.cpp
* Fix invalid iterator in idf_common.cpp
* Fix unitialized scalar value in vrml_layer.cpp

* Fix unitialized variable in MSG_PANEL_ITEM default ctor.
* Fix a bunch of uncaught exception issues.
* Fix a memory leak in the NETLIST_READER::GetNetlistReader() when an
  an attempt to read an invalid net list file occurs.

* Add support for VRML DEF coordinate key word.
* Coding policy fixes by Blair Bonnett <blair.bonnett@gmail.com>
* Debugging output clean up.

This method is added for scripting purposes, to be able to query
specific board layer names thru a board object.

If no board specific layer name is found, it will fallback to
standard layer names.

Now OpenGL can report its problems instead of shutting down the application.

* Add test to CMakeLists.txt to verify wxPython is installed when
  KICAD_SCRIPTING_WXPYTHON=ON.
* Add test to make sure wxPython version major and minor numbers match
  the version of wxWidgets found.
* Add code to set the correct version of wxPython to the python scripting
  initialization code.
* Minor code simplification in Pcbnew KIFACE main window creation.

Rename eeschema/dialogs/dialog_sch_find.fbp to dialog_schematic_find_base.fbp, to be consistent with other dialogs. 
Pcbnew run from the project manager: add menu Save Copy As..., which is the same command as Save As ... in stand alone mode, but with the constraints of a project (no cwd change, no board filename change, and keep project settings)

Extend arrays and duplicate to pcbnew (GAL and legacy), covering modules, text, lines, tracks, dimensions and targets.

Text arrays can now use "%s" as a placeholder to be substituted with the array index.

Also expand menu options for move exact, arrays and duplicate.

Minor fixes for arrays - use proper unit parsing, add numbering start for circular arrays

Add circle radius indicator to array dialogue

Pcbnew: Fix Bug #1420074 (Crash when a footprint is added to the board (or edited) from the footprint editor, if a new pad was added, because the net info of the new pad is broken in this case)

Pcbnew: fix ver minor issues. ModEdit: fix issue in GAL mode: when importing a footprint from the footprint wizard, the new footprint was not shown.

Prevent Pcbnew edit graphics property dialog from excepting zero length objects.  (fixes lp:1392117)