Working on webgl lighting vis.  Removed spritesheet canvas from 2 approaches.

Because we can draw to copy buffer canvases directly from the sprite image,
we do not need to first draw that image to a canvas and then copy from
there.  The only exception is the approach where we calculate the depths
on the client side.
Implemented rudimentary lighting.
Debugging normals, also added grunt watch to detect shader changes.
Problem with normals was actually problem using incorrect sprite offset.
More work on dynamic rendering.

Fixed cartoon shading problem, hooked up rendering widget, added LUT.
Added an extra background rendering pass so we can control bg color.
Removed specular highlights from surfaces pointing away from light.
Adding script to generate some new dynamic rendering data.
Removed hardcoded layer names, light either side of surfaces, add new script.
Merge branch 'add-webgl-lighting-capability' into add-webgl-lighting-capability-merge
Fix search which was broken by overflow hidden, also hide fps info again.
Moved data generation script into a new folder.
Changes to pass style checks.
Merge pull request #79 from Kitware/add-webgl-lighting-capability-merge

Add webgl lighting capability merge