Add support for Minecraft Pocket Edition worlds

Feature request (and potential pipedream):

It would be helpful to allow the renderer to read worlds created by Minecraft Pocket Edition.

PE worlds contain one RegionFile in little-endian (!) format, and chunks are not Gzipped or wrapped in NBT.

See the code in PocketInvEditor: https://github.com/zhuowei/PocketInvEditor/blob/master/src/net/zhuoweizhang/pocketinveditor/io/region/RegionFile.java for an implementation example. I guess a modification of World and Region should take care of it.

For more info: http://www.minecraftwiki.net/wiki/Pocket_Edition_Level_Format

Start by reading the World and Region code, then compare their region and chunk handling with the PocketInvEditor RegionFile.java implementation linked in the issue. Check the Minecraft Pocket Edition Level Format reference for the little-endian region file and unwrapped, non-Gzipped NBT details. Done means the renderer can read and render Pocket Edition worlds.

Written by the indexing model from the issue text.