QmlDesigner: Use defaultNodeAbstractProperty

Change-Id: Ifa16795d6cca1256b86b69ab9f7da3e0644aec48
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Remove unused QmlItemNode::defaultPropertyChildren

Change-Id: If20457a3d7f6017421b360a77c452395ff0e9219
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Do not use ModelNodeOperations outside of DesignerActions

The ModelNodeOperations are an implementation detail of our
DesignerActions and should not be used in other places.

Change-Id: I495bfd043a6b1dd89952b0e7d2318e429678640b
Reviewed-by: Marco Bubke <marco.bubke@digia.com>
QmlDesigner: move goIntoComponent() to DocumentManager.

Move ComponentUtils::goIntoComponent() to DocumentManager.

Change-Id: I038f4c56cb1745455613a1dbdeeb8bcb927da7f3
Reviewed-by: Marco Bubke <marco.bubke@digia.com>