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/hunting_blind.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="M11 0L11 7.94L12.49 14.39C12.55 14.66 12.38 14.93 12.11 14.99C11.87 15.04 11.63 14.92 11.54 14.7L11.51 14.61L11.29 13.64L7.5 10.97L3.71 13.64L3.49 14.61C3.43 14.88 3.16 15.05 2.89 14.99C2.65 14.93 2.49 14.71 2.5 14.48L2.51 14.39L4 7.94L4 1L11 0ZM10.23 9.05L8.37 10.36L10.95 12.18L10.23 9.05ZM4.77 9.05L4.05 12.18L6.63 10.36L4.77 9.05ZM9.98 8L5.02 8L7.5 9.75L9.98 8ZM7 3L5 3L5 4L7 4L7 3ZM10 3L8 3L8 4L10 4L10 3Z"/>
+</svg>