Move almost everything to private classes.
Assimp loading restored.
All examples working.
QNode hierachy is now handled through QObject::setParent, addChild,
removeChild are part of the private api.
Note: commented QChangeArbiter unit tests as they can no longer work with this
patch and will restore them when QChangeArbiter will have been made private.
Task-number: QTBUG-41470
Task-number: QTBUG-41523
Change-Id: I4430974b3aa7f3744c38714b451b122e0cb4d0c9
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>