ENH: Use sample TubeTK appl. boilerplate code for TubeGraphToImage.

Change-Id: If6ea6ca1ecb58a6e3c7dc6a12ead0177a83f0a77
Merge topic 'rk-GenericFix'

ff64c9c ENH: Use sample TubeTK appl. boilerplate code for TubeGraphToImage.