OSX: Move libraries from PlugIns/ to Frameworks/
other: move QmlDesigner plugins to plugins directory

Change-Id: Ia266a3514ce6a496061daa044b3781daae0bc272
Reviewed-by: Christian Stenger <christian.stenger@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>