Improvements to the MBS framework
 - Detection Algorithm can work around rotated structures (in the x-z plane)
 - Added WorldBlock iterator to WorldChunk, yet it includes every block in world.
 - Forced BlockStructure to create TileStructure rather than TileEntity.
 - TileStructure has the coordinates of the "central" tile entity, so all the functionality can be redirected there.
Merge remote-tracking branch 'origin/master'