Debugger: List QObject methods and signals in dumper

This mostly re-activates code from the old code path
in the QObject dumper.

Task-number: QTCREATORBUG-11997

Change-Id: Ie3e6eddffe8d0edd7d5947c2eec03d707bd2436b
Reviewed-by: Christian Stenger <christian.stenger@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>