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/gown.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="M9 1C8.5 2 8 2.5 7.5 2.5C7 2.5 6.5 2 6 1C5 1.33 4.5 2 4.5 3C4.5 4.5 6 5 6 7.5C6 9.17 4.33 10.33 1 11C1 11.67 1.33 12.33 2 13C3 14 4 13 5 13C6 13 6 14 7.5 14C9 14 9 13 10 13C11 13 12 14 13 13C13.67 12.33 14 11.67 14 11C10.67 10.33 9 9.17 9 7.5C9 5 10.5 4.5 10.5 3C10.5 2 10 1.33 9 1Z"/>
+</svg>