Chunks are now saved to disk using protobuf only. No java object seri…

…alization any more!

Note: Old worlds can still be loaded and are converted into the new storage format.

+ added additional decode() method to interface ProtobufHandler<T, M>
* updated file Chunks.proto to reflect latest changes in chunk storage
* updated class WorldRenderer to support the new storage format
* extended interface ChunkStore with new methods saveToFile(File) and loadFromFile(File)

* lots of changes to class ChunkStoreProtobuf to implement the new storage format
+ added support for threads monitoring to class ChunkStoreProtobuf
+ added subclass ProtobufHandler to class ChunkStoreProtobuf

src/main/java/org/terasology/io/ProtobufHandler.java

@@ -15,4 +15,6 @@ public interface ProtobufHandler<T, M extends MessageOrBuilder> {
 
     public T decode(M message);
 
+    public void decode(M message, T value);
+
 }