[z1910] Add commands for MMaps

Added commands are:
.mmap [on|off] to show state of mmaps, or to enable/disable mmaps globally
.mmap stats to show information about current state of mmaps
.mmap loadedtiles to show which tiles are currently loaded
.mmap path to calculate and show a path to current select unit
.mmap loc to print on which tile one is
.mmap testarea to calculate paths for all nearby npcs to player

Authorship goes to qsa in addition

(cleaned version of a913619)

(based on commit [s1491] - d624892)