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-dashes.svg

@@ -0,0 +1,11 @@
+<?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 0.5L4.5 0.5L4.5 3L3 3z"/>
+  <path d="M3 8.5L4.5 8.5L4.5 11L3 11z"/>
+  <path d="M3 12.5L4.5 12.5L4.5 15L3 15z"/>
+  <path d="M3 4.5L4.5 4.5L4.5 7L3 7z"/>
+  <path d="M10.5 0.5L12 0.5L12 3L10.5 3z"/>
+  <path d="M10.5 8.5L12 8.5L12 11L10.5 11z"/>
+  <path d="M10.5 12.5L12 12.5L12 15L10.5 15z"/>
+  <path d="M10.5 4.5L12 4.5L12 7L10.5 7z"/>
+</svg>