1) put compass reading strip above perspective view
2) handle GPS coords in other formats: Waypoint+, etc.
3) draw waypoints and single route/track points as dots.
4) Test Alaska DEMs (They have different scales in x and y.  Do something
more intelligent than average to get m2grid.)
5) Make the control window a pop-up menu accessible from psp window.
6) contrast control
7) FIX: vexagger makes FOV calculation incorrect
8) tile datum
9) Eye height changes when crossing tile boundary. Fix?
10) My graphics card messes up clipping on 2D triangles. Fix?
11) FIX: black gap between inner square and boundary with 10 meter data
