Created ModelicaTest.OverdeterminedInitialization package for testing of high-index, overdetermined initialization problems, as decided at the 80th Design Meeting (see also #968)
Moved all relevant models in there

git-svn-id: https://svn.modelica.org/projects/Modelica/trunk@7194 7ce873d0-865f-4ce7-a662-4bb36ea78beb