Added a new Tile.
Removed temporary "grass_flat.collider" table
Changed around some of the code to do with cloning tiles.
Also tiles no longer have a "image" variable.
Tiles custom colliders can no longer be outside of their tilespace.
Added code for garbage collection.
Changed world size to 300x300 instead of 100x100
When drawing tiles it now gets the image of the imageKey from the tile