* clean up the object parent-child relation mechanism.  Rather large
  code cleanup, that simplifies a lot of code..  Needed a
  backwards-compatible file format extension.  This commit now also
  adds proper treatment of internal objects, because it no longer
  relies on the inherently wrong isInternal() hack, but features The
  Correct Fix(tm).

svn path=/trunk/kdeedu/kig/; revision=229606