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/rumble_strip.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg viewBox="0 0 15 15" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <path d="M0 8L15 8L15 10L0 10L0 8ZM1 6.5L2 6.5C2.55 6.5 3 6.95 3 7.5L3 8L0 8L0 7.5C0 6.95 0.45 6.5 1 6.5ZM5 6.5L6 6.5C6.55 6.5 7 6.95 7 7.5L7 8L4 8L4 7.5C4 6.95 4.45 6.5 5 6.5ZM9 6.5L10 6.5C10.55 6.5 11 6.95 11 7.5L11 8L8 8L8 7.5C8 6.95 8.45 6.5 9 6.5ZM13 6.5L14 6.5C14.55 6.5 15 6.95 15 7.5L15 8L12 8L12 7.5C12 6.95 12.45 6.5 13 6.5Z"/>
+</svg>