Use local variables in partials

simplify the viz_opts partial to use local variables passed from the main template.
Refactor generating visualization facet

Move calculating facet counts to the Prism model from the Prism Controller
Refactor view partials
Removes unused methods on PrismController

the #validate_colors method is never called (and should be on the Facet model anyway
Update gems
Merge branch 'develop'