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 saw how the code in "World#calculateSkyLightSubtracted" and "World#getSunBrightness" works,
and I discovered that there are some similarity with them.
I copied the similar part, and made it to a function for the mods which use sun brightness factor on the server side.