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/radiation.svg

@@ -0,0 +1,4 @@
+<?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">
+  <path d="M9 9L12 14C9 15 6 15 3 14L6 9C7 9.75 8 9.75 9 9zM11 0.5L8.5 4.75C9.5 5.25 10 6.25 10 7L15 7C15 4 14 2 11 0.5zM4 0.5C1 2 0 4 0 7L5 7C5 6.25 5.5 5.25 6.5 4.75L4 0.5zM9 7C9 6.25 8.25 5.5 7.5 5.5C6.75 5.5 6 6.25 6 7C6 7.75 6.75 8.5 7.5 8.5C8.25 8.5 9 7.75 9 7z"/>
+</svg>