[ent] Compile ent/various's hacc stuff into one file
[ent shell world] Try to add a Crate object.
[phys] Make Object::pos optional
[ent] Add ROD mixin (Resident Object Drawn)
[ent] Make Crate.Object optional
[ent] Forgot to add mixins.h
[phys] Add command for toggling phys debug layer
[ent] Make Crate work better.
[vis] Add draw_texture
[util] Allow adding Rects and Vecs.
[ent] Make stuff rendering simpler
[ent] Forgot to make sure Resident::finish() was called
[phys] Default mass should be 0, not NAN.
[ent vis] Fix draw_texture (and crate's use of it)