Added Support for Hopper Metadata Rotation

Added code for SchematicLoader so that hoppers will rotate properly.
This was probably not considered an issue before we had support for tile
entity exports and imports. Now it's critical that we support hoppers.
There are other blocks that are still not supported - we should really
fix this in the future so that all blocks will rotate. The code for this
is overly complicated - we should look into a simpler method.