* Use wxAuiManager perspective to save and load window settings which should
  allow us to start using more advanced wxAui features like detachable tool
  bars and windows.
* Remove sash size change events, event handler, and sash width clamping code
  since it didn't work all that well anyway.
* Disable the close button on the footprint view pane.
* Update the footprint list box selection when iterating the list using the
  tool bar arrow buttons.
* Merge code from modview.cpp into modview_frame.cpp and remove modview.cpp.