* 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.
* 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.