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/crossing_tram_striped.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="M0.74 9L2.88 6L1.41 6L0 7.97L0 5L2.12 5L5.5 5L5.5 6L4.41 6L2.26 9L3.74 9L5.5 6.53L5.5 10L0 10L0 9L0.74 9ZM14.26 6L12.12 9L13.59 9L15 7.03L15 10L9.5 10L9.5 9L10.59 9L12.74 6L11.26 6L9.5 8.47L9.5 5L15 5L15 6L14.26 6ZM8 0L9 0L9 15L8 15L8 0ZM6 0L7 0L7 15L6 15L6 0Z"/>
+</svg>