MEMBER thing1 thing2

	if "thing2" is a word or list and if MEMBERP with these inputs would
	output TRUE, outputs the portion of "thing2" from the first instance
	of "thing1" to the end.  If MEMBERP would output FALSE, outputs the
	empty word or list according to the type of "thing2".  It is an error
	for "thing2" to be an array.