resID can be either an integer or a string. It is the
id or the name of the map to be unloaded.
Unloading from memory means
the space used by the map can be freed up for other things (usually
loading a different map).
Call this command if the map
will no longer be used by the application. It can be loaded up
again without any problems.
If this map was the currently
active map then subsequent map calls will not work until a call
to Set Current Map has been made.