[vis] Only apply scale to vert_pos
[rata] Direction must be signed.
Revert "[phys rata] s/Ambulator/Feet, make stats constants"

This reverts commit a985dbff3430952b027e502a5ec1b3d6180a7213.
[ent rata] Add Biped class.
[tool/make.pm] Implement user-defined auto-subdeps.

Allowing such things as generating subdeps from #include statements
[make] Fix subdep generator code
[hacc] Make some library includes <> instead of ""
Remove a billion now-automated subdeps
Change various includes from "" to <>
[vis] Start adding text rendering
[ent phys] Some modifications to walking
[ent rata] Make sure ground objects have friction.
[phys] gravity = 30
[ent] Walking friction depends on space gravity
[ent] Biped walk animation depends on distance walked
[vis] Complete text drawing
[rata] Add a monospace font and test text
[vis] Add displayability of an in-game console
[vis] Darken screen when using console
[core] Start implementing console.