* 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.
* 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.