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/railway_track_partial.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="M10.5 11L10.5 14L4.5 14L4.5 11L10.5 11ZM12.5 11L13.5 11C13.78 11 14 11.22 14 11.5L14 13.5C14 13.78 13.78 14 13.5 14L12.5 14L12.5 13L13 13L13 12L12.5 12L12.5 11ZM10.5 6L10.5 9L4.5 9L4.5 6L10.5 6L10.5 6ZM12.5 6L13.5 6C13.78 6 14 6.22 14 6.5L14 8.5C14 8.78 13.78 9 13.5 9L12.5 9L12.5 8L13 8L13 7L12.5 7L12.5 6ZM2.5 11L2.5 12L2 12L2 13L2.5 13L2.5 14L1.5 14C1.22 14 1 13.78 1 13.5L1 11.5C1 11.22 1.22 11 1.5 11L2.5 11ZM2.5 6L2.5 7L2 7L2 8L2.5 8L2.5 9L1.5 9C1.22 9 1 8.78 1 8.5L1 6.5C1 6.22 1.22 6 1.5 6L2.5 6ZM3 1L4 1L4 15L3 15L3 1ZM11 1L12 1L12 15L11 15L11 1Z"/>
+</svg>