I've made several attempts at writing a Tailgunner clone in C for the Vectrex over the years -
this may be my final attempt, but the work in progress is already looking a lot better than the
previous efforts and I have applied all the tricks I've learned over the years to specifically
reduce the CPU requirements when running on the Vectrex.

I'm now recreating it bottom up, tackling the difficult parts first.  The easy stuff (the
user interface) can be added from one of the earlier versions once the hard stuff (the 3D
flight mechanics and object rendering) is working.

As of today the rendering is working but not finished, and the flight path mechanics is well
underway.  I'm confident this time that I will be able to finish the project.

The demo flightpath in the current upload is *NOT* a working one.  I'm in the middle of
debugging a problem with the orientation of the model axes.  Bear with me!

Vide users please note the only file you need is vide-main.c which has been generated
from tg.c with the includes expanded inline to avoid the problems with including .c
files in Vide, where they don't inherit the defines of the parent file..