Serialize (Osg)PointCloudRepresentation, add UnitTests
Rewrite TransferOdeStateToVerticesBehavior so that it can be serialized

1. Two new behaviors: TransferPhysicsToGraphicsMeshBehavior and
   TransferPhysicsToPointCloudBehaivor.
   They both have about the same API: they transfer information from a
   source to a target.
   Source being Physics and Target be graphics.
   Since (Osg)PointCloudRepresentation is a template, it is treated
   slightly different.

2. Update StapingDemo main.cpp to use the new behaviors

3. Update UnitTests which use TransferOdeStateToVerticesBehavior to use
   the new behaviors.
Fix a bug when deserializing PoseComponent in SceneElement
Make a new Stapling example utilizes serialization feature.