Refactored handle-map-events to dispatch to handle-viewby-events and handle-submission-events
Added a toggle function; fixed remove-nil to also work with boolean vectors (and read nicer :)
Calculating selected-answers based on button clicks.
Highlighting the answer based on whether it is selected
Changed the color palette of view-by to include more saturated colors. (Re: #429, @rowo, have a look at these colors. I took the high saturation colorbrewer palette, and put the more saturated colors up front. Also disabled red + brown because they clash with the :clicked color.)
Coloring the deselected answers grey, and bringing the selected markers to the front
When answer is selected, everything else goes grey, as opposed to being highlighted. Also added hover actions.
Converted the list of answers from a series of <li><a class="pure-button"> .. to being inside a pure-menu div, which makes the hovers and clicks look much better.
Adding some tests to ona.utils.seq for good measure