Plumbing for custom color classes
Various plumbing tweaks / fixes
Renders the customBgStylesheet based on the user's chosen colors
Renders the custom backgrounds into the presentations
Explicitly sets the color on spectrum when closing the color chooser modal

This resolves an issue where the most recently selected colors were not present.
Updated the flat theme
jsdoc
Fixed alignment, removed log statement
Merge pull request #239 from tantaman/custom-bgs

Custom background colors