Variables: Use %{Env:SOME_NAME} to access environment variables

Change-Id: I2291e91608f9a93b7c886890a1e1039c5002f4ce
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
QmlDesigner: Do the dirty test only for non node instances

The test should stop at the next node instance.

Change-Id: I99daf1215edea34b36434720c44ea7844c4bef34
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Add a special root item of the view too

Change-Id: Ie7cc58d3793717fce979ccd554060b91bc0d7040
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>