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/sculpture.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="M6 12L5 10.5L6 9L5 7.5L6 6L5 4.5L6 3L5 3L4 1L11 1L10 3L9 3L10 4.5L9 6L10 7.5L9 9L10 10.5L9 12L11 12L11 13L12 13L12 14L3 14L3 13L4 13L4 12L6 12L6 12ZM6.5 4.5L7.5 5.5L8.5 4.5L7.5 3.5L6.5 4.5ZM6.5 7.5L7.5 8.5L8.5 7.5L7.5 6.5L6.5 7.5ZM6.5 10.5L7.5 11.5L8.5 10.5L7.5 9.5L6.5 10.5Z"/>
+</svg>