BUG: finish update to VTK6 by using SetInputData

A few missing instances were spotted where python methods weren't
update to check for the current VTK version and use SetInput if
used with VTK version less than 6 or SetInputData otherwise.
Removed some unnecessary spaces.
Merge pull request #43 from naucoin/FinishUpdateToVTK6

BUG: finish update to VTK6 by using SetInputData