SetImageConnection(a) is the same as SetInputConnection(1,a)
where, a=vtkAlgorithmOutput*

vtkImageDifference changes:
Use GetInputConnection(0,0) instead of GetInput()
Use GetInputConnection(1,0) instead of GetImage()

For a filter to do GetWholeExtent,
instead of,
   extent = filter.GetOutput().GetWholeExtent()
new method is,
   extent = filter.GetExecutive().GetWholeExtent(filter.GetOutputInformation(0))

For a vtkImageData object, SetWholeExtent and SetUpdateExtent methods are not required.

STYLE: When an image test fails, upload full size pngs to the dashboard rather than shrunken jpegs.  This allows test writers to get comparison images directly from the dashboard.  Size is no longer an issue on the dashboard since it does file comparisons and keeps only one copy around as a test fails for multiple days.

ENH: Patch from Prabhu: failed test images now go to Testing/Temporary instead of to the VTKData directory.

class level attributes that were references to VTK objects.  These should be
fixed now.

compare an image rather than a render window with a saved image.  The
compareImage function now uses this function internally.

when they know the test is run interactively.

BUG: Renamed ExitAbort to ExitError in vtkDebugLeaks.  It now calls exit(1) instead of abort().  This avoids the popup dialog on Windows.

ENH: Added vtkDebugLeaks::ExitAbort flag that is enabled by default when running tests for a dashboard.  This will cause vtkDebugLeaks to call abort() when leaks are detected which will make the tests fail.