Update version to 2.5.3-SNAPSHOT
Fix more compile errors in Forge, fix NBT logic

When fixing compile error in the Forge version, I discovered a bug in
the Bukkit version. NBT lists tags with other things than compound tags
will now be copied properly.

Metrics isn't updated for Forge 1.7.2, so it has been removed for now.
It can be brought back when an update is out.
Fix cave and ravine generation on WorldHeightCapBits:7. Fixes #239.

The byte[] array is now always 8-bits, but the caves and canyons where
still using it sometimes as if it were a 7-bit array.
Some more compile fixes for the Forge version
Merge branch master into feature-BioInherit-VirtBiomeId
Cleanup the code a bit

- Reduced method length and complexity. Tasks are now done is smaller
methods.
- Delegated folder searching to a new class, BiomeConfigFinder.
- Added a BiomeIds class to manage the real and virtual biome ids.
- Fix problems when a BiomeConfig of a vanilla biome was in both the
world and global folder.

Note: virtual biomes are still not implemented in Forge.
Note2: the network code has not been tested yet.