Add walkthrough lib to the Review page
Add reviewTime change to walkthrough in Review page
Add human-readable timelabel
Fix LeafLet directive
introduce code to handle map zoom event
introduce glyphs for narrative step controls
Fix walkthrough on dragging the map
Merge branch 'features/eugene/review-walkthrough' of github.com:IanMayo/mustard into features/eugene/review-walkthrough
Hide walkthrough when Review page disappears
Fix digest process
Merge pull request #47 from IanMayo/features/eugene/review-walkthrough

Great work - a huge new piece of functionality. Thanks Eugene.