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/quakerism.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg viewBox="0 0 15 15" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <path d="M10.88 6.13L15 7.5L10.88 8.87L10.27 7.5L10.88 6.13ZM8.87 10.88L7.5 15L6.13 10.88L7.5 10.27L8.87 10.88ZM4.12 8.87L0 7.5L4.12 6.13L4.73 7.5L4.12 8.87ZM6.13 4.12L7.5 0L8.87 4.12L7.5 4.73L6.13 4.12ZM4 4L7.5 5.55L11 4L9.45 7.5L11 11L7.5 9.45L4 11L5.55 7.5L4 4Z"/>
+</svg>