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/balloon.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 0C10.5 0 12.5 2.5 12.5 6C12.5 10 8 13 8 13C8 13 8.5 14 8.5 14.5C8.5 15 6.5 15 6.5 14.5C6.5 14 7 13 7 13C7 13 2.5 10 2.5 6C2.5 2.5 4.5 0 7.5 0zM7.5 1C4.5 1 3 4.5 3.5 6.5C4 4.5 5.5 2 7.5 1z"/>
+</svg>