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/windmill.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" id="windmill" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M6,5L3.5,7.5l1,1L7,6V5.5L7.5,5L8,5.5V6l2.5,2.5l1-1L9,5H8.5L8,4.5L8.5,4H9l2.5-2.5l-1-1L8,3v0.5L7.5,4L7,3.5V3L4.5,0.5&#xA;&#x9;l-1,1L6,4h0.5L7,4.5L6.5,5H6z M11.5,13h-1l-1-4l-2-2l-2,2l-1,4h-1C3.2239,13,3,13.2238,3,13.5C3,13.7761,3.2239,14,3.5,14h8&#xA;&#x9;c0.2761,0,0.5-0.2239,0.5-0.5C12,13.2238,11.7761,13,11.5,13z M8,13H7v-1.5024C7,11.2228,7.2228,11,7.4976,11&#xA;&#x9;C7.7751,11,8,11.2249,8,11.5024V13z"/>
+</svg>