Tile collisions

Although theoretically it would have already been possible to let
entities collide with tiles, it is now part of the engine itself and
also very easy to use.
If you want to add tile collidables to a collision test list you're
preparing, call
level.getOtherCollidables(list, getCollisionShape(level));
and it will add all tiles (and theoretically also all other collidables
in that area (except for entities)) to the list so you can perform the
test with tiles added.