Added UIElement.VisualParent accessor.
Added DependencyObject.SetCurrentValue to allow updating of 2-way bindings.
Fixed TransformCollection adding to collection.
Initialized Polygon.Points and Polyline.Point to a collection.
Now warning when DependencyObject.SetValue swallows an error.
Will not spit out binding path warnings if target is not attached.
No longer registering RowDefinition/ColumnDefinition properties as core dependency properties.