Fix for initializing Mystcraft dims with chunkloaders.
Use ints instead of bytes for dimension in ServerConfigManager (Should fix #919 -- please check)
Only do MV's fake chunk clear trick on MV dimensions -- Major Mystcraft perf speedup for clients!
Merge pull request #988 from OniBait/MC147-RCFix

Minor fixes and one Major perf fix for Mystcraft dims on client-side.