QmlDesigner: Prepare for dropping items from item library to navigator

Change-Id: I7de6ffc61ae04e25df93e355f820205732867af6
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Add QmlItemNode::createQmlItemNode overload

We need in the navigator a function that takes a parent property instead
of a node.

Change-Id: Ia91c8d3e4eea87cc8f49c409eb987e3187a6b316
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Item dropping from the item library to the navigator

Change-Id: I04f3b809ce743bbeef5e3955892ab51690783942
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Add QmlItemNode::createQmlItemNodeFromImage overload

We need a parent property overload so we can add a item to a non
default property.

Change-Id: I2044126f1c9f4cb112d1b96db163b70cd12b9042
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Handle drops of images from the item library in the navigator

Change-Id: I42c0224d5f6aadc7253113b39d7c4ababeab45fb
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Fix pointer return value

Change-Id: I60d6744753856c536db61484fa59a6756b9ec5d3
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>
QmlDesigner: Don't reparent if the new parent property is the same

Change-Id: I5de80a9896c17e22e52b5cc1e209c728cfd5616f
Reviewed-by: Tim Jenssen <tim.jenssen@digia.com>