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-dots.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="M5.5 1.5C5.5 3.5 2.5 3.5 2.5 1.5C2.5 -0.5 5.5 -0.5 5.5 1.5z"/>
+  <path d="M12.5 1.5C12.5 3.5 9.5 3.5 9.5 1.5C9.5 -0.5 12.5 -0.5 12.5 1.5z"/>
+  <path d="M5.5 13.5C5.5 15.5 2.5 15.5 2.5 13.5C2.5 11.5 5.5 11.5 5.5 13.5z"/>
+  <path d="M12.5 13.5C12.5 15.5 9.5 15.5 9.5 13.5C9.5 11.5 12.5 11.5 12.5 13.5z"/>
+  <path d="M5.5 5.5C5.5 7.5 2.5 7.5 2.5 5.5C2.5 3.5 5.5 3.5 5.5 5.5z"/>
+  <path d="M12.5 5.5C12.5 7.5 9.5 7.5 9.5 5.5C9.5 3.5 12.5 3.5 12.5 5.5z"/>
+  <path d="M5.5 9.5C5.5 11.5 2.5 11.5 2.5 9.5C2.5 7.5 5.5 7.5 5.5 9.5z"/>
+  <path d="M12.5 9.5C12.5 11.5 9.5 11.5 9.5 9.5C9.5 7.5 12.5 7.5 12.5 9.5z"/>
+</svg>