* Add event handler to check all button clicks for default command event
IDs and handle them appropriately by either calling EndQuasiModal() or
passing the event up the event handler chain to allow the default dialog
handlers to perform their magic.
* Add event handler to handle the close window event properly.
* Add scope brackets so the wxBusyCursor will stop being displayed when
the footprint library loading is complete in CvPcb.
* Remove the artificial footprint library read error limit to prevent
potentially readable libraries from being loaded after the error limit
is reached.
* Change error message dialog to an HTML dialog so that potentially large
error messages can be displayed with scrolling and the ability to copy
and paste the error message for bug reporting purposes.
* Add busy cursor when loading the footprint libraries so the user has some
idea that something is happening while the footprint libraries are being
loaded.
