Manifold fixes of Pocket Dungeons

There is nothing original here. Please refer to the original [Pocket Dungeons](http://www.thingiverse.com/thing:59110). The Goblin Hunter, Thief and Elf have been fixed up in Blender to make them manifold so that the latest Slic3r can slice them. The rest have merely been separated from the full ( non-split) plate for individual printing.