New weather

Makes weather behave in a reasonable manner and be saved in just a single int.
Removes acid rain because there's no good way to implement it.
Removes the weather debug menu because it needs to change a lot, but is not really that necessary.
Old savefiles may experience a sudden weather change after loading due to the old weather stuff just being ignored completely and replaced by this.
Things that will need some testing:
Right now the weather is checked for every turn. In my machine this works fine, but lower end may experience slowness when waiting/crafting.
Large arrays of funnels left working in an unloaded chunk may cause lag when loaded again the longer they were left unloaded.
The radio station code that makes weather reports is completely untested. It is also totally accurate currently. No randomness added.