40C3: tours, schedule data, tour map and calendar entries

- tour-map shortcode: Leaflet map of the tour locations with routes from the
  Congress, from the map/tours sections of data/schedule/<event>.yaml; Leaflet
  and the OSMIC, Maki and Temaki icon sets vendored; 39C3 uMap data converted.
- calendar shortcode: per tour date, a pill with an .ics download (iCalendar)
  and a Google Calendar link; Font Awesome Free vendored, fa-icon partial.
- README sections for the calendar and tour map shortcodes and the map data.

assets/vendor/icons/temaki/vending_cold_drink.svg

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0" y="0" viewBox="0 0 15 15">
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+  <path d="M5 3.75C5 3.75 5 3.75 5 3.75C5 4.25 6.5 4.35 7 4.35C7.5 4.35 9 4.25 9 3.75C9 3.75 9 8.75 9 8.75C9 9.75 5 9.75 5 8.75C5 8.75 5 3.75 5 3.75zM7.9 3.26C8.15 3.26 8.35 3.33 8.35 3.41C8.35 3.49 8.15 3.56 7.9 3.56C7.66 3.56 7.46 3.49 7.46 3.41C7.46 3.33 7.66 3.26 7.9 3.26zM9 3.25C9 2.75 7 2.75 7 2.75C7 2.75 5 2.75 5 3.25C5 3.75 6 4 7 4C8 4 9 3.75 9 3.25z"/>
+</svg>