Box objects (AABB) now have the long awaited extent() and center()
methods. Corners are now called “aa” and “bb” for convenience. The
WorldEntity class uses a box3 for its AABB instead of two vec3s.
This allows us to simplify a lot of verbose code.

and 2) fuck the Visual Studio compiler that crashes when confused.

scene so that g_scene can be deprecated later.

joystick class, and put a header in each source file.