Implemented disk reading once lsh limit is reached

Also now writing lsh tables to ../tmp/lsh subdirectory, in case other stuff is being written to tmp
Right, so I'm saying use the subdir that's created in setUp(), so you know it will be cleaned up later.

Deleting everything in tmp is bad practice because could be harmful to other programs. For instance, what would we do if our temp files were deleted by another program in the middle of our execution?