Added protobuf support for the Chunk class. Switched to protobuf to store new worlds.

+ added Chunks class which is responsible for mod extensions of chunk data and supports encoding and decoding of chunks into protobuf messages
+ added interface ProtobufHandler<T, M> to implement encoders and decoders for protobuf messages
+ added static class ProtobufHandler to Chunk class
+ added ChunkStoreProtobuf which uses protobuf internally to store chunks

* internally renamed the liquid data into extra data
* added checks to AdvancedConfig to make sure it does not throw if some settings can't be found
* updated Chunks.proto to support mod extensions of chunk data
* updated WorldRenderer to use ChunkStoreProtobuf instead of ChunkStoreGZip