Modified AuthorizationUI.py

[Justin Binns]

I've got a modified AuthorizationUI.py that I'm checking in to CVS.  I
don't *know* that it won't break other platforms, but I don't think it
will.  I did make some semi-major changes to support the Mac (I got rid
of the SashLayout stuff, as in the Venue Client, and I added an
alternative ListBox mechanism since the CheckListBox isn't supported
under wxMac or wxCarbon).  If folks have problems, let me know.  If we
have to roll back, of course, we can (that's the great thing about CVS
;-).

Justin