non-pair mods, tile defs, basic wiz mode

non-paired mods (i.e. not addstr/decstr, but just one mod), tile
definitions (should make save file neater and smaller), basic wiz mode
which allows for level editing live, spawning items/actors what not, and
saving/loading levels. still pretty hacky, but seems to work ok. split
tile and tiledef to their own file