Basic multiblock, still buggy.
Validation logic has been improved. Can check in 4 direction orientations. A few bugs are left, though.
Fixed a bug in validation logic.
Add a manager that keeps track of multi blocks and resets all blocks that were once part of complete structure. So now removing any block will reset the whole structure.
Multi manager now provides a shared tile for the whole structure and the container and a tile is shared among them.