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/cliff_falling_rocks.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="M2 1L3.75 1C3.91 1 4.06 1.07 4.15 1.2L7 5L6 10L9 12L9.82 13.64C9.88 13.76 9.83 13.91 9.71 13.97C9.67 13.99 9.63 14 9.6 14L2 14C1.45 14 1 13.55 1 13L1 2C1 1.45 1.45 1 2 1ZM9.43 5.03L11.68 5.78C11.83 5.83 11.95 5.94 12 6.09L12.76 8.38C12.85 8.64 12.71 8.93 12.44 9.01L10.11 9.79C9.99 9.83 9.85 9.82 9.73 9.76L8.28 9.03C8.07 8.93 7.96 8.69 8.01 8.47L8.79 5.38C8.85 5.11 9.13 4.95 9.39 5.02C9.41 5.02 9.42 5.02 9.43 5.03ZM11 12.33L11 11.14C11 10.95 11.11 10.78 11.28 10.69L12.63 10.02C12.84 9.91 13.11 9.97 13.25 10.16L14.18 11.41C14.35 11.63 14.3 11.94 14.08 12.11C14.08 12.11 14.07 12.12 14.06 12.12L13.13 12.75C13.04 12.8 12.95 12.83 12.85 12.83L11.5 12.83C11.22 12.83 11 12.61 11 12.33Z"/>
+</svg>