DESCRIPTION:

Toggle the autopilot mode. Currently the following bits
control the behaviour:
0x01 Enable the autopilot
0x02 Enable automatic forward movement
0x04 Enable automatic turning
0x08 Enable sliding for collision avoidance
0x10 Enable rolling to simulate gravity
0x20 Enable turning around when dead ends are reached
0x40 Enable marker dropping

The behaviour of the autopilot can be influenced by setting
serveral parameters within the $root.module.internal
hierarchy. Currently the following members exist:
.rolldown: vector (x/y/z) telling where "down" is, when rolling
             is activated
.rollspeed: relative speed of rolling motions. 1.0 is normal.
             Do not set too high, as this might cause oscillations.
.slidespeed: relative speed of sliding motions. 1.0 is normal.