void follow (string dest [, int method [, mixed extra ]])
void follow (object dest [, int method [, mixed extra ]])
If this object is a follower of some object, every move of that object will a cause to this object's follow().
Normal use is to let e.g. cats run after their owner, but this mechanism can also be used to let tools be notified about every move of their owner.
Default behaviour of /std/thing/moving is to move into the same <dest> as the other object, unless P_NOFOLLOW is set.