Added Land Marker item
Label sign improvements
- Label sign positions are now stored relative to the block's facing direction, so reappear on the correct side if the block is broken & replaced in a different direction.
- Line 0 (block name) now includes a Unicode symbol indicating where the front of the block is (e.g a sign on the back of the block has a ▼ symbol)
- Signs now stay attached if the block is moved by a piston (unless obstructed, in which case they pop off)