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/cooling_tower_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="M12 1C10 6 14 12 14 14C13 15 2 15 1 14C1 12 5 6 3 1C3 0 12 0 12 1zM8.2 10.18C7.73 10.54 7.27 10.54 6.8 10.18L5.4 12.63C6.8 13.12 8.2 13.12 9.6 12.63L8.2 10.18zM7.5 8.46C7.15 8.46 6.8 8.82 6.8 9.19C6.8 9.56 7.15 9.93 7.5 9.93C7.85 9.93 8.2 9.56 8.2 9.19C8.2 8.82 7.85 8.46 7.5 8.46zM5.87 6C4.47 6.74 4 7.72 4 9.19L6.33 9.19C6.33 8.82 6.57 8.33 7.03 8.09L5.87 6zM9.13 6L7.97 8.09C8.43 8.33 8.67 8.82 8.67 9.19L11 9.19C11 7.72 10.53 6.74 9.13 6z"/>
+</svg>