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/railway_signals.svg

@@ -0,0 +1,4 @@
+<?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" x="0" y="0" viewBox="0 0 15 15">
+  <path d="M9.21 1.5C10.48 1.5 11.5 2.53 11.5 3.81L11.5 11.19C11.5 12.47 10.48 13.5 9.21 13.5L5.79 13.5C4.52 13.5 3.5 12.47 3.5 11.19L3.5 3.81C3.5 2.53 4.52 1.5 5.79 1.5L9.21 1.5zM7.5 8.5C6.67 8.5 6 9.17 6 10C6 10.83 6.67 11.5 7.5 11.5C8.33 11.5 9 10.83 9 10C9 9.17 8.33 8.5 7.5 8.5zM7.5 3.5C6.67 3.5 6 4.17 6 5C6 5.83 6.67 6.5 7.5 6.5C8.33 6.5 9 5.83 9 5C9 4.17 8.33 3.5 7.5 3.5z"/>
+</svg>