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/waterfall.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="15" height="15" viewBox="0 0 15 15" xmlns="http://www.w3.org/2000/svg" id="waterfall">
+  <path d="M14 1H5C3.34315 1 2 2.34314 2 4V8.87918C1.39704 9.28261 1 9.96937 1 10.75C1 11.9927 2.00736 13 3.25 13C3.7127 13 4.14279 12.8599 4.5 12.6209C4.85721 12.8599 5.2873 13 5.75 13C6.28601 13 6.77826 12.812 7.16413 12.5H7.51743C8.01909 12.8165 8.61403 13 9.25 13C11.0449 13 12.5 11.5449 12.5 9.75002C12.5 8.39777 11.6747 7.23919 10.5 6.74934V5C10.5 3.89543 11.3954 3 12.5 3H14V1ZM11.5 9.75C11.5 10.9926 10.4926 12 9.25 12C8.71418 12 8.2221 11.8127 7.83567 11.5H6.75009C6.52204 11.8036 6.15895 12 5.75 12C5.34105 12 4.97796 11.8036 4.74991 11.5H4.25009C4.02204 11.8036 3.65895 12 3.25 12C2.55964 12 2 11.4404 2 10.75C2 10.1453 2.42944 9.64082 3 9.525V5.75C3 5.33579 3.33579 5 3.75 5C4.16421 5 4.5 5.33579 4.5 5.75V9C4.5 9.27614 4.72386 9.5 5 9.5C5.27614 9.5 5.5 9.27614 5.5 9V6.75C5.5 6.33579 5.83579 6 6.25 6C6.66421 6 7 6.33579 7 6.75V9C7 9.27614 7.22386 9.5 7.5 9.5C7.77614 9.5 8 9.27614 8 9V5.75C8 5.33579 8.33579 5 8.75 5C9.16421 5 9.5 5.33579 9.5 5.75V7.51373C10.625 7.63809 11.5 8.59186 11.5 9.75Z"/>
+</svg>