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/shrub_low.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="M12.5 13L2 13C0.9 13 0 12.1 0 11C0 9.9 0.9 9 2 9C2.01 9 2.03 9 2.04 9C2.01 8.84 2 8.67 2 8.5C2 7.12 2.9 6 4 6C4.37 6 4.72 6.13 5.02 6.35C5.01 6.23 5 6.12 5 6C5 4.34 6.12 3 7.5 3C8.68 3 9.67 3.98 9.93 5.31C10.24 5.11 10.61 5 11 5C12.1 5 13 5.9 13 7C13 7.37 12.9 7.71 12.73 8.01C14 8.12 15 9.2 15 10.5C15 11.88 13.88 13 12.5 13Z"/>
+</svg>