Set part of selected thing's memory of the game map to string argument: the line
of the argument's number.
+T_MEMDEPTHMAP [0 to 255] [string]
+Set part of selected thing's game map memory depth map to string argument: the
+line of the argument's number.
+
T_MEMTHING [0 to 255] [0 to 255] [0 to 255]
Add to selected thing's memory of things on map thing of ID of first argument,
y position of second argument and x position of third argument.