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/maki/cafe.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" id="cafe" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M12,5h-2V3H2v4c0.0133,2.2091,1.8149,3.9891,4.024,3.9758C7.4345,10.9673,8.7362,10.2166,9.45,9H12c1.1046,0,2-0.8954,2-2&#xA;&#x9;S13.1046,5,12,5z M12,8H9.86C9.9487,7.6739,9.9958,7.3379,10,7V6h2c0.5523,0,1,0.4477,1,1S12.5523,8,12,8z M10,12.5&#xA;&#x9;c0,0.2761-0.2239,0.5-0.5,0.5h-7C2.2239,13,2,12.7761,2,12.5S2.2239,12,2.5,12h7C9.7761,12,10,12.2239,10,12.5z"/>
+</svg>