inherit_list() - get a list of parents of an object
string *inherit_list( object obj );
Returns an array of filenames of objects inherited by obj. Only
directly inherited files are returned. E.g. if A inherits B which
inherits C, inherit_list(A) will return an array with B, but not C.
If no object is supplied, this efun will default to this_object().
deep_inherit_list(3), inherits(3)