code: public Created setCreated(Date created) {
  		Created prop = (created == null) ? null : new Created(created);
  		setCreated(prop);
  		return prop;
  	}
docs: Sets the date-time that the journal entry was initially created.
  @param created the creation date-time or null to remove
  @return the property that was created
  @see <a href="http://tools.ietf.org/html/rfc5545#page-136">RFC 5545
  p.136</a>
  @see <a href="http://tools.ietf.org/html/rfc2445#page-129">RFC 2445
  p.129-30</a>