* 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.
* 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.