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/ruins.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="M1 5.5C1 5 4 5 4 5.5C4 5.5 4 13 4 13C4 13.5 1 13.5 1 13C1 13 1 5.5 1 5.5zM6 5.5C6 5.5 6 13 6 13C6 13.5 9 13.5 9 13C9 13 9 5.5 9 5.5C9 5 6 5 6 5.5zM11.5 6.5C11 6 9 8 9.5 8.5C9.5 8.5 13 13 13 13C13.5 13.5 14.5 13.5 15 13C14 12 14 10.5 14.5 10C14.5 10 11.5 6.5 11.5 6.5zM6 1.5L1 1.5C0.5 1.5 0.5 4.5 1 4.5C1 4.5 9 4.5 9 4.5C9.5 4.5 9.5 2.5 9 2.5C7.5 2.5 6 2 6 1.5z"/>
+</svg>