Removed CONTAININGUSER from gasharl mapEntrySchema

In favor of using the standard getParentInvid() and getParentObj()
methods on mapEntryCustom objects
Made the user object refresh map entry labels when they are edited. (gasharl)
Fixed an NPE I just introduced in the gasharl mapEntryCustom

finalizeSetValue() shouldn't order the client to refresh the
entry's label when, say, the containing invid is being set, as
the getParentInvid() method returns null at that time.