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/aerialway.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" id="aerialway" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M13,5H8V2.6c0.1854-0.1047,0.3325-0.2659,0.42-0.46L13.5,1.5C13.7761,1.5,14,1.2761,14,1s-0.2239-0.5-0.5-0.5L8.28,1.15&#xA;&#x9;C8.0954,0.9037,7.8077,0.7562,7.5,0.75C7.0963,0.752,6.7334,0.9966,6.58,1.37L1.5,2C1.2239,2,1,2.2239,1,2.5S1.2239,3,1.5,3&#xA;&#x9;l5.22-0.65C6.7967,2.4503,6.8917,2.5351,7,2.6V5H2C1.4477,5,1,5.4477,1,6v7c0,0.5523,0.4477,1,1,1h11c0.5523,0,1-0.4477,1-1V6&#xA;&#x9;C14,5.4477,13.5523,5,13,5z M7,11H3V7h4V11z M12,11H8V7h4V11z"/>
+</svg>