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/wheel.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="M7.5 0C11.75 0 15 3.5 15 7.5C15 11.5 11.75 15 7.5 15C3.25 15 0 11.75 0 7.5C0 3.25 3.25 0 7.5 0zM6 9.25C6 9.25 3.13 11.25 3.13 11.25C3.13 11.25 4.5 13.25 7.5 13.25C10.5 13.25 11.88 11.25 11.88 11.25C11.88 11.25 9 9.25 9 9.25C8.06 9.88 6.94 9.88 6 9.25zM6.5 1.75C4 2.25 1.75 4.75 1.75 7.5C1.75 9.06 2.19 9.69 2.19 9.69C2.19 9.69 5.25 7.75 5.25 7.75C5.25 7.75 5 6.25 6.5 5.5C6.5 5.5 6.5 1.75 6.5 1.75zM8.5 1.75C8.5 1.75 8.5 5.5 8.5 5.5C10 6.25 9.75 7.75 9.75 7.75C9.75 7.75 12.81 9.69 12.81 9.69C12.81 9.69 13.25 9 13.25 7.5C13.25 4.75 11 2.25 8.5 1.75z"/>
+</svg>