* First pass at collidable linksets

* There will be bugs, you can count on that. To avoid them, set the linksets phantom
* After region restart, the linksets restore in a non collidable state.
* Linksets can but shouldn't be made physical with the physical checkbox or when you unlink them, they tend to explode.
* After creating a linkset, you have to move the linkset or set it phantom and not phantom for it to become collidable.   
* There's a few ParentGroup references that need to be refactored.

OpenSim/Region/Environment/Scenes/InnerScene.cs

@@ -170,6 +170,7 @@ namespace OpenSim.Region.Environment.Scenes
             foreach (SceneObjectPart part in sceneObject.Children.Values)
             {
                 part.LocalID = m_parentScene.PrimIDAllocate();
+                
             }
             sceneObject.UpdateParentIDs();
             AddEntity(sceneObject);