Skylight Hooks for Minecraft Forge

World Hooks on sky light, which can provide sunlight / moon factor from the Worldprovider.
mainly for Solar/Lunar Eclipse.

getSunBrightnessFactor is for getting sun brightness, i think it is better than just using getCelestialAngle.. I don't see any problem on it.
I fixed the exc file. I think this is ready to go when the above discussion ends.