Update script for generating 2d mpas data supporting value coloring.

Added programmable filter to grab out ith tuple from data arrays. Also
added cell to point data filter, because it seems the rgbzview plugin
does not correctly support cell data in all cases.
Added new view/widget to display dynamic rendering with lookuptable only.

This view is for data with value coloring (lookuptable support), but with
no lighting information.
Support disabling pieces of the rendering widget upon construction.
Style fix.
Hide canvases only needed for background rendering.
Merge pull request #97 from Kitware/add-webgl-lut-only-view

Add webgl lut only view