Moving Deformation Field Visualizer into its own extension

Moving Deformation Field Visualizer from SlicerRT into its own extension and renaming it to Transform Visualizer.

https://www.assembla.com/code/slicerrt/subversion/nodes/1072/trunk/TransformVisualizer/src

www.slicer.org/slicerWiki/index.php/Documentation/Nightly/Extensions/TransformVisualizer