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/height_restrictor.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="M2.13 3.13L2.13 14.13L0.88 14.13L0.88 1.5C0.88 1.15 1.15 0.88 1.5 0.88C1.85 0.88 2.13 1.15 2.13 1.5L2.13 1.88L12.88 1.88L12.88 1.5C12.88 1.15 13.15 0.88 13.5 0.88C13.85 0.88 14.13 1.15 14.13 1.5L14.13 14.13L12.88 14.13L12.88 3.13L11 3.13L11 4L10.65 4L8.65 6L6.85 6L8.85 4L10 4L10 3.13L5 3.13L5 4L5.65 4L3.65 6L3.5 6C3.22 6 3 5.78 3 5.5L3 4.5C3 4.22 3.22 4 3.5 4L4 4L4 3.13L2.13 3.13ZM8.15 4L6.15 6L4.35 6L6.35 4L8.15 4ZM11.35 4L11.5 4C11.78 4 12 4.22 12 4.5L12 5.5C12 5.78 11.78 6 11.5 6L9.35 6L11.35 4L11.35 4Z"/>
+</svg>