Bug fix for large maps

Maps weren't drawing mountains in tile numbers greater than the tile
size due to a bug in reading the wrong size constraint. This is now
fixed. Also fixed a "bug" where rivers would exit off the side of the
map and re-enter in the next tile, although it's really just a
preference to kill them off for good. Also modified debug enable
messages - didn't need the "ALL" debug message since individual
categories already have dedicated enable flags.