Update
In this update:
Here's 50 some dwarves digging away. Industrious little fellas aren't they?

- Better idle dwarf behavior
- Weather temporarily disabled pending performance fixes.
- Tree spreading temporarily disabled pending performance fixes.
- Performance improvements.
- Fixed a bug where a seedling could grow into approximately infinite plants.
Here's 50 some dwarves digging away. Industrious little fellas aren't they?
