Now the method can be used to get the fully qualified name of
destructors, operator-ids and conversion-function-ids.

Done-with: Erik Verbruggen

Done-with: Erik Verbruggen

I hate this commit, but unfortunately, I don't have time right now
to finish the new template instantion algorithm so I have to
enable the old way of doing instantiations.

If it encounters a forward declaration, it tries to find the class
declaration globally now.

Task-number: QTCREATORBUG-20

Also fixed the tests for it.