We now store Visualizations, VisualizationAnimations, and
VisualizationSets as three separate lists linked by tag strings.
WARNING: this breaks existing projects with visualizations. The
test projects have been updated.
Added comments, renamed files, removed cruft.
Stop showing the visualization tag name in the code list. It's
often redundant with the code label, and it's distracting. (We may
want to make this an option so you can Ctrl+F to find a tag.)
