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/american-football.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" id="american-football" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M7.53,3C3.09,3,1,7.5,1,7.5S3.09,12,7.53,12S14,7.5,14,7.5S12,3,7.53,3z M11,7v1.5C11,8.7761,10.7761,9,10.5,9&#xA;&#x9;S10,8.7761,10,8.5V8H8v0.5C8,8.7761,7.7761,9,7.5,9S7,8.7761,7,8.5V8H5v0.5C5,8.7761,4.7761,9,4.5,9S4,8.7761,4,8.5v-2&#xA;&#x9;C4,6.2239,4.2239,6,4.5,6S5,6.2239,5,6.5V7h2V6.5C7,6.2239,7.2239,6,7.5,6S8,6.2239,8,6.5V7h2V6.5C10,6.2239,10.2239,6,10.5,6&#xA;&#x9;S11,6.2239,11,6.5V7z"/>
+</svg>