Adds "8-bit graphics" test level
Adds test level, implements paths for new tiles.
This TMX has some properties in the patient objects which could eventually be used to pull in details for the level.
Patient spawner attributes are loaded from the TMX file
* See issue #6 for some documentation on defining patient spawners in the TMX.
* Fixes bug with attempting to close path on unrecognized tile type
Minor code cleanup
WIP - implement immediate turning