QmlDesigner: Remove operator from properties

To improve the readability of the source methods should be used.

Change-Id: I839e448369a03dc42b3649baed033daa20c4d49a
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Add more selection functions in SelectionContext

It is much smarter to use the view functions instead of generating the whole
list and pick the first item or ask if the list is empty.

Change-Id: Ifcd40784ddab75c505b5f7f2dfc7b11cbd11c69d
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Refactor allQmlItemsRecursive

Change-Id: If8b98e008e59de1eae87108a3256005fd85981b9
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Add hasDefaultNodeAbstracProperty to ModelNode

Change-Id: I421686cdc9faf2a9dadad3162cfbfc6793ab3caf
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Remove notifier from QmlModelView

Change-Id: Ieee0fc5fc95832d6976f0c1397e0261164f317c3
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>