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/poster_box.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="M3 9.5L3 14L7.5 14L12 14L12 5.5L12 1L7.5 1L3 1L3 9.5ZM4 10.5L4 2L8.5 2L11 4.5L11 13L6.5 13L4 10.5ZM2.5 0L12.5 0C12.78 0 13 0.22 13 0.5L13 14.5C13 14.78 12.78 15 12.5 15L2.5 15C2.22 15 2 14.78 2 14.5L2 0.5C2 0.22 2.22 0 2.5 0ZM9 1L12 1L12 4L9 1ZM3 11L6 14L3 14L3 11ZM5.5 4C5.22 4 5 4.22 5 4.5C5 4.78 5.22 5 5.5 5L8.5 5C8.78 5 9 4.78 9 4.5C9 4.22 8.78 4 8.5 4L5.5 4ZM5.5 6C5.22 6 5 6.22 5 6.5C5 6.78 5.22 7 5.5 7L6.5 7C6.78 7 7 6.78 7 6.5C7 6.22 6.78 6 6.5 6L5.5 6Z"/>
+</svg>