Revision 1851

Rework the projection dialog to fix a few bugs, including RT 2166
and most of 2168

(ProjFrame): Substantial changes
throughout the class. The main change is to use the ProjectionList
class instead of a normal wxListBox. Also, add an explicit
"Unknown" projection to the projection choice control.
(ProjPanel.__init__): Add an "unknown" ellipsoid
(TMPanel.__init__, LCCPanel.__init__): Tweak the order of
instantiation of the panel's controls to make the tab-order more
natural