Basic mcpc+/forge world support.

This allows tardises to travel to modded/non-NORMAL environment dimensions when using MCPC+. It fixes teleportation within these dimensions, and the biome search feature.

It's not pretty, but it seems to work OK.

Something's buggy with commands and entering/exiting tardis, but I don't believe it's related to my changes, it seems to affect a build from original source as well.