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/bread.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="M3 11.5C3 11.5 4 10 4 10C4 10 9 9 4.5 9C4.5 9 5.5 7.5 5.5 7.5C5.5 7.5 10.5 6.5 6 6.5C6 6.5 7 5 7 5C7 5 12 4 7.5 4C7.5 4 9 2 9 2C11.5 -1 14.5 0.5 11.5 5.5C11.5 5.5 7 12.5 7 12.5C4.5 16.5 1 15 3 11.5z"/>
+</svg>