Should allow Pcbnew code easier to change and Gerbview code more understandable and easier to maintain.
Code cleaning (remove dead code, add comments).
Minor other enhancements.

Other scaling factors (MILS_TO_IU_SCALING_FACTOR and DECIMILS_TO_IU_SCALING_FACTOR)
also defined only in convert_to_biu.h.
Allows different scaling value for Gerbview.
Needs more tests.

* Replace C malloc() and free() functions with C++ new and delete
  operators or the appropriate STL container.
* Add option to end mouse capture function to skip executing the end
  mouse capture callback.
* Lots of coding policy and Doxygen comment goodness.

* Grammar and spelling fixes in Eeschema, CvPcb, and Pcbnew path and
  library dialog tool tips.
* Translate the French file name subrill.cpp to highlight.cpp.
* Lots of coding style policy fixes.

* Correct all user strings and comments for the correct capitalization of
  application names according to JP.  They are KiCad, Pcbnew, CvPcb,
  Eeschema, and GerbView.
* Add a note the the user interface policy about the correct capitalization.

* Move auto save time global variables into PCB_EDIT_FRAME object.
* Move footprint library name list global variable int PCB_EDIT_FRAME
  object.
* Improve library back up and temporary file error message strings and make
  them translatable.
* PCBNew string unification.
* Translate French code names and comments.
* Coding style policy and Doxygen comment fixes.

* All header files used to create the PCB common library now compile as
  stand alone code.  This prevents the need to define them in a specific
  order to make source code compile properly.  It should also now be
  possible to relocate the source code to build the common PCB library
  to a separate folder.

* Move various locate functions into the appropriate board item object.
* Unified best zoom for all frames derived from PCB_BASE_FRAME.
* Remove track.cpp as it is no longer needed.
* Dead code removal.
* Remove scary frame window pointer member from board item objects.
* Add draw bounding box to gerber draw item for debugging purposes.

All: use double instead of int to store zoom values.

* 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.

Gerbview:   Added: read Excellon files created by Pcbnew. The full Excellon command set is not supported, but drill files created by Pcbnew are supported.