Add missing build files, improve Mesa beaches

Mesa beaches now change their height based on the water level of the
biome/world.
Attempt at fixing buildscript, update to latest Forge

See the platforms/forge/build.gradle file for more information. I'm
looking for a better fix.

Also updated to latest Forge, so we can get rid of most obfuscated
names.
Merge branch master into feature-BioInherit-VirtBiomeId