World resource spawning

I’ve been working on getting resources to spawn in the world. Resources can be allocated to a skill, then when a world tile spawns we check to see if any skill wants to spawn a resource on that tile.

Currently, mining and woodcutting can spawn resources (ores and trees respectively). Mining has two different ores which can spawn and woodcutting just a single tree. The spawn rate is currently set per-skill, but longer term this will be moved to be per-resources to allow for more rare ores/trees etc…