Goo code drop

Goo added
When the player collides with Goo, they become infected
Goo appears under player when they walk if they are "infected"
Goo disappears when the ritual is completed, but only in a radius around
the player. The player must do the ritual to disinfect themselves
Made the darkness close in faster to fit with new scheme.
Added some hacky sorting to make the goo appear under the player at all
times
Added games now know their "grid position" as well as their actual
position.
Added functionality to remove objects from the game world
Exposed "trigger" collision box functionality, for non-solid objects
Added collision callback functionality