WORLDEDIT-2220 - Reported by Gus.Callaway

Currently, if you select a polygonal area and save it as a schematic, the area is saved as a cuboid, not as a polygon. I am not sure if this is necessary based on the format of a schematic file, but it is really quite annoying. I want to be able to rollback a specific area using a schematic without worrying about rolling back everything around that area.