Added proper world support for Mystcraft. Fixed IC2 texture bug when using MV.

* Mystcraft dimensions will now load during server initialization.
* Fixed Mystcraft not correctly saving properly.
* All Mystcraft dimensions will be stored in world_myst/age#
* Fixed IC2 texture orientation not facing up when using MultiVerse.
* All forge dimensions will now be created in root with following naming
convention : world_environment
ex.
Twilight  -> world_twilightforest
Mystcraft -> world_myst

Note: If you have existing Mystcraft dimensions, move them to the following location world_myst/ageXX where XX is the age dimension.If you create a new Mystcraft dimension, you will need to restart the server so MultiVerse can pick it up. Make sure you force a save before restart so the proper mystcraft agedata is created. All agedata is still created in world/data/agedata_XX.