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/valley.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="M3 14L1.5 14C0.67 14 0 13.33 0 12.5L0 10.5L0 6.7L2.2 1.53C2.34 1.21 2.65 1 3 1C3.35 1 3.66 1.21 3.8 1.53L7 9L7.5 10.5C8.31 11.14 8.48 11.64 8 12C7.52 12.36 5.86 13.03 3 14ZM9 14C9 14 9.33 13.67 10 13C11.29 11.71 10.51 10.72 7.65 10.04L8 9L11.2 1.53C11.34 1.21 11.65 1 12 1C12.35 1 12.66 1.21 12.8 1.53L15 6.7L15 10.75L15 12.5C15 13.33 14.33 14 13.5 14L9 14ZM3 2.25L1 7L3 6L4 8L5 7L3 2.25ZM12 2.25L10 7L12 6L13 8L14 7L12 2.25Z"/>
+</svg>