ElementalBlock returns!

- Merged BlockRotateable and BlockContainerRotateable into
ElementalBlockContainer then renamed ElementalBlockContainer to
ElementalBlock
- Switched all blocks to use the new ElementalBlock
- Gave the block breaker it's own texture set
- All instances of ElementalBlock now drop their inventory when broken
- Fixed bug where generator would consume non-burnable items
- reverted turret logic to try to shoot the nearest thing (the
persistent target thing wasn't working out)