some bug fix to run Jeff test bug
Fix bug in prepFillArea.
Optimize prepFillArea.

Rather than allocating (and rendering!) a unique polydata + mapper + actor
combo for each vertical slice of the color bar, create a single, multicell
polydata that gets rendered at once in a single actor/mapper.

This speeds up the execution of prepFillArea using the test script in #849
from 0.25s to 0.09s on my machine.
Disable level compression in banded contour filter.

Ref #851.
Add regression test.
Update VTKPlots.py

removing print statement
Update VTKPlots.py

another print statement removed
Changes VisTrails URL to Github
Merge branch 'master' into 851-preserve-labels
Merge pull request #880 from UV-CDAT/851-preserve-labels

851 preserve labels
Merge pull request #881 from UV-CDAT/use-github-vistrails

Changes VisTrails URL to Github
Merge branch 'master' into 849_prepFillAreaCleanup
Merge pull request #877 from UV-CDAT/849_prepFillAreaCleanup

849 prep fill area cleanup
Fix devide-by-zero error and update ctest images
Fix slice position init
Merge remote-tracking branch 'origin/vcs3D-fix-unexpected-error-884' into vcsDV3D-2.2-features
Hide z slider for 2D plots