#3 Stuttering while loading new chunks

[CJ Kucera]

While moving around the map, there's a visible framerate drop when the new chunks get loaded in. I'll have to investigate ways to eliminate that - ideally I want it to be smooth enough that you don't even notice the loading.

Relatedly, once I have that working properly, it should be pretty trivial to have some background chunk loading which will actively precache the chunks (thus populating the minimap), which would go a long way towards making the minimap more useful.