Log message for revision 71227:
  Step 4: Make aq_get aware of __parent__ pointers.
  (Also some comment cosmetics in _Acquisition.c)

Log message for revision 71228:
  Test aq_parent property as well (in addition to aq_parent function)

Log message for revision 71229:
  Step 5: Make aq_chain aware of __parent__ pointers.