Base PhysicsComponent; Update levels submodule;

table.merge is now recursive.
Components now merge in non-action variables and functions.
Entities will now have a state table to encapsulate all non-core data
members.
Merge branch 'sheen' of https://github.com/ifdm/overgrowth into sheen

Conflicts:
	class/player.lua
	require.lua
	states/game.lua