[gamelib-devel] Documentation updates, some general fix-up

[Ingvar]

The 3D documentation has been gently overhauled.

The games-3d ASDF system file was, ahem, not named correctly. That's been 
fixed.

Assorted legacy code has been mercilessly ripped out of shapes.lisp (no, we do 
NOT need to special-case tanks).

Some code has been moved to globals-3d.

Next on the list is "more documentation and illustrative images".

//Ingvar