Fallback changes, most of moons fallbacks.

Here is a bit rewritten getfallback function, it now returns Fallback pointer.
Also, there are some moons fallbacks, but probably not all that could be used. The values are sometimes hard to import here.
At the end, I've unlocked bloodmoon weather, but it's currently unused, maybe I'll try to implement it later.

P.S. Size values in sky.cpp should rest commented, as I've done, because they're different than new moons sizes. I've tested new moons size, and it looks good, but it's good idea to have them somethere in case of problems.