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/crossing_markings-zebra_paired.svg

@@ -0,0 +1,9 @@
+<?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" viewBox="0 0 15 15">
+  <path d="M3 0.5L12 0.5L12 1.5L3 1.5z"/>
+  <path d="M3 2.5L12 2.5L12 3.5L3 3.5z"/>
+  <path d="M3 6L12 6L12 7L3 7z"/>
+  <path d="M3 8L12 8L12 9L3 9z"/>
+  <path d="M3 11.5L12 11.5L12 12.5L3 12.5z"/>
+  <path d="M3 13.5L12 13.5L12 14.5L3 14.5z"/>
+</svg>