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/chicane_arrow.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 3.33L4 4L7 0L10 4L8 3.33L8 5.5L11.6 8.2C12.13 8.6 12.13 9.4 11.6 9.8L8 12.5L8 15L6 15L6 12C6 11.69 6.15 11.39 6.4 11.2L9.33 9L6.4 6.8C6.15 6.61 6 6.31 6 6L6 3.33Z"/>
+</svg>