Adds an adminverb to write map files.

Created by: PJB3005

Map files are stored in data/logs/saved_maps, as such they can be retried with .getserverlog, however the admin that started a write will also get the file sent to him with the ftp() proc.

Note: map files exported still need a lot of cleaning afterwards (literally every turf has redundant variables that might even break things written to them).