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/dentist.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" id="dentist" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M4.36,14c-1,0-0.56-2.67-0.86-5c-0.1-0.76-1-1.49-1.12-2.06C2,5,1.39,1.44,3.66,1S6,3,7.54,3s1.57-2.36,3.85-2&#xA;&#x9;s1.59,3.9,1.29,5.9c-0.1,0.45-1.1,1.48-1.18,2.06c-0.33,2.4,0.32,5-0.8,5c-0.93,0-1.32-2.72-2-4.5C8.43,8.63,8.06,8,7.54,8&#xA;&#x9;C6,8,5.75,14,4.36,14z"/>
+</svg>