* 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.
* 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.
* CVPcb now uses wxUpdateUIEvent instead of set toolbars.
* Removed duplicate event handlers in CVPcb that were factored into
EDA_DRAW_FRAME.
* Fix definition of GeneralControle() in CVPcb that prevented it from being
called.
* Remove rarely used and scary refresh code GeneralControle() method in all
main frame windows.
* Factor zoom menu and tool bar command IDs down to EDA_DRAW_FRAME.
Wayne Stambaugh
jean-pierre charras
Dick Hollenbeck
charras