Create flight boundary & add entropy to controls

This is my first crack at this.  Still not quite working right.  The
plane takes large sweeping arcs at the high and low end boundaries.
Entropy code started but no effect seen yet when run.
Change entropy with W/S keys
First "working" version of boundaries/entropy
Made entropy less jerky, cleaned out some dead commented code
Sort of fixed the plane rendering, more changes needed.
Merge in Jeff's changes.
A few cleanups.