Before redoing much of enemy render

Treating the enemy /like/ a wall but wanting it drawn reduced in scale,
and scaling the debug rays, hides proper way to do ray trace and z
order.

Going to throw out much of the code until I get z order right, and then
might redo /again/ after looking up a proper raycasting fps and copying
it.
Minimap and mapgen improvements

No progress on enemy render, although I found some examples to help me
along.

Rather, maps now have a boundary wall and a margin between the wall and
random wall generation, and all entities including the player spawn
within the boundary.