Began making entities defined as classes
Updated explosion test to use new system
Discovered entity __index problem

Projectiles made with hump.class weren't working properly. I think this
has something to do with fields not being found in the object, because
they are from a parent class and are provided with __index. More testing
is required.
Decoupled event system and CES
Removed debug things from Physics.lua
Projectile creation copies metatable
Fixed projectile metamethod issues

Projectiles now seem to work!
Merge branch 'wip'

Conflicts:
	entities/projectiles/generic.lua
Cleanup up weapon creation in game.lua