Add a Test level

The test level is not yet done but it already has all collision blocks, some moving platforms, water nodes, info nodes and spawn nodes.

I would still like to add breakable blocks, killing floor, bouncers and a whole bunch of enemies.

Going forward I would like to have at least one example of every node type in this level to help with level building, with the added benefit of being able to test on low frame rates, I think this will be especially helpful for testing collisions.