Allow an object class to be provided in an attribute description list,

Allow an object class to be provided in an attribute description list,
treated as a request for all required and allowed attributes of the class.
This allows:
	ldapsearch (objectClass=*) inetOrgPerson
	(requests return of all attributes of inetOrgPerson)
and
	ldapsearch (objectClass=*) extensibleObject
	(requests return of all attributes, e.g., "+" "*")