Refactoring of class chunk

* renamed class WorldView into ClassicWorldView and made it deprecated
+ added a comment to the class ClassicWorldView indicating all the classes which have to be refactored further
Refactoring of class Chunk

* moved enum type State into its own file and renamed it to ChunkState
* simplified enum type ChunkState

+ added enum type ChunkType
- removed some constants from class Chunk because ChunkType is now responsible for that.
* updated lots of classes to use the apropriate ChunkType instead of Chunk
* updated encoding/decoding of Chunks into/from protobuf messages to incorporate ChunkType and handle ChunkState correctly

* updated unit tests

Chunk.proto

- removed definition of enum type State
* changed message Chunk to use uint32 instead of State
+ added chunk type to message Chunk
Refactoring of class Chunk

* renamed package org.terasology.world.localChunkProvider into org.terasology.world.chunks.provider
* moved classes ChunkProvider, LocalChunkProvider and ChunkReadyEvent into package ...world.chunks.provider
* renamed package ...world.chunks.store into ...world.chunks.storage
* moved ChunkStore into package ...world.chunks.storage
* made class ChunkStoreGZip deprecated
+ added method size() to class TeraArrayIterator
Some preliminary work for stackable chunks.

+ added terrain generator StackableTestGenerator for testing of stackable chunks
* changed class InitialiseWorld to use StackableTestGenerator if the default chunk is stackable.
* changed lots of classes to either use ChunkType.Default or, if possible, a passed in ChunkType
* moved chunk- and block position related methods in TeraMath into ChunkType
+ added support for chunk type and stackable chunks to ClassicWorldView
+ added support for chunk type and stackable chunks in LocalChunkProvider
+ added support for chunk type in all world providers
* changed simple lock in class Chunk to read/write lock
* extended class ChunkType to handle more chunk related stuff
+ added a preliminary, experimental WorldView class to implement a new view concept
* changed lots of tests to use ChunkType