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/maki/skiing.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" id="skiing" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M15,4.5C15,5.3284,14.3284,6,13.5,6S12,5.3284,12,4.5S12.6716,3,13.5,3S15,3.6716,15,4.5z M13.72,11.89&#xA;&#x9;c-0.0623-0.1197-0.2083-0.1684-0.33-0.11c-0.6846,0.4194-1.5208,0.5111-2.28,0.25L4.78,8.86L7.5,7.5v-3L9,5.25v3L10.5,9L12,8.25&#xA;&#x9;L10.5,7.5V3l-3-1.5L6,2.25v4.5L3.28,8.11L0.61,6.78C0.4857,6.7192,0.3358,6.7707,0.275,6.895C0.2142,7.0193,0.2657,7.1692,0.39,7.23&#xA;&#x9;l10.5,5.25c0.3156,0.135,0.6568,0.1998,1,0.19c0.5998-0.0103,1.1889-0.161,1.72-0.44c0.1236-0.0615,0.174-0.2116,0.1125-0.3352&#xA;&#x9;C13.7217,11.8932,13.7208,11.8916,13.72,11.89z"/>
+</svg>