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/checkpoint.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="M14 7L14 13.5C14 13.5 14 13.5 14 13.5C14 13.78 13.77 14 13.5 14L8 13.98L14 7ZM7 13.5L7 9L2 9C1.45 9 1 8.55 1 8C1 7.45 1.45 7 2 7L12.5 7L7 13.5ZM13 3.5C13 4.88 11.88 6 10.5 6C9.12 6 8 4.88 8 3.5C8 2.12 9.12 1 10.5 1C11.88 1 13 2.12 13 3.5Z"/>
+</svg>