QmlDesigner: avoid setContext warning if there is already one

Change-Id: I2d23f8f18cce11bdfbdcb4a8d9d6d99fec7d20e6
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: improve error output of the puppets

 - errors -> warning none false outputs -> debug
 - adding some more error outputs

Change-Id: Ice61d10a87dc5ef789b7913cae166641b18ddf27
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: move setObjectOwnership

 - to the same position like in the other methods

Change-Id: Ie12147de0e9030a35928a2c0a5dd38d34f998845
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>