Day 34

Casey decided to start offloading tile map definitions to separate files so I took the time to also cleanup some of the organization of the code.
I'm still keeping some cpp files directly included within engine.cpp and win32_platform.cpp for now (instead of their translation unit files). I'll problably wait till much later to offload them.

Making that first baby step for procedural gen, and proper tile_chunk memory felt pretty good after many vods of stumbling.