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/post_box.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 1C6.5 1 5 3 5 5C5 5 5 14.5 5 14.5C5 15 7 15 7 14.5C7 14.5 7 12 7 12L11 12C11 12 11 14.5 11 14.5C11 15 13 15 13 14.5C13 14.5 13 5 13 5C13 3 11.5 1 9 1zM1.5 1L3.5 5C3.5 3 4 1.5 6 1L1.5 1z"/>
+</svg>