Merge topic 'better_sprites'

96b994f1 Fix shadowed var
57daf0bc Some more features and some cleanup reorg.
44e33c4a Cleanup comments
091552c1 Add ability to adjust the table size
edc24bde Improve the capabilities of the vtkPointGaussianMapper

Acked-by: Kitware Robot <kwrobot@kitware.com>
Tested-by: Scott Wittenburg <scott.wittenburg@kitware.com>
Reviewed-by: Utkarsh Ayachit <utkarsh.ayachit@kitware.com>
Merge-request: !489