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/milk_jug.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" x="0" y="0" viewBox="0 0 15 15">
+  <path d="M4 1C3.29 0.29 11.71 0.29 11 1C11 1 9.5 2 9.5 2C9 2.5 9.5 3.5 10 3.75C10.5 3.5 11 3 11.5 3.5C12 4 11.5 4.5 10.75 5C10.75 5 11 5.5 11 6C11 6.5 11 13.5 11 13.5C11 14.5 4 14.5 4 13.5C4 13.5 4 6.5 4 6C4 5.5 4.25 5 4.25 5C3.5 4.5 3 4 3.5 3.5C4 3 4.5 3.5 5 3.75C5.5 3.5 6 2.5 5.5 2C5.5 2 4 1 4 1z"/>
+</svg>