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/lawn.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg viewBox="0 0 15 15" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <path d="M7.5 3C6.17 5.25 6.17 8.25 7.5 12C7.27 12 6.27 12 4.5 12C4.5 6.55 5.5 3.55 7.5 3ZM4.5 3C3.17 5.25 3.17 8.25 4.5 12C4.27 12 3.27 12 1.5 12C1.5 6.55 2.5 3.55 4.5 3ZM10.5 3C9.17 5.25 9.17 8.25 10.5 12C10.27 12 9.27 12 7.5 12C7.5 6.55 8.5 3.55 10.5 3ZM13.5 3C12.17 5.25 12.17 8.25 13.5 12C13.27 12 12.27 12 10.5 12C10.5 6.55 11.5 3.55 13.5 3Z"/>
+</svg>