UndergroundBiomesConstructs

v43 - constructs changed from tile entities to multiple metadata'd blocks. For compatibility with old world, the tile entity blocks still exist but there is no way to make more; the recipes create only the new blocks. As yet there is no conversion from the old blocks or items; they continue to exist.

The alpha designation applies to converted worlds. New world should be fine.

Also, support provided for high speed generation in RTG worlds.