Enable DrawBounds by default.
Made PlateView readonly
Added total plate count to plate collection.
return the success state on export.
Changed plate export name format.
Removed old way of adding parts before support for drag-n-drop was added.
Set pathsNeedUpdated when a part moves.

Trying to keep the fact that PlateView uses GraphicsPath private. Nothing outside of the control should worry about how the plateview operates, just that it works.