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/skiing.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg version="1.2" baseProfile="tiny" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 50 50" overflow="inherit">
+  <path d="M44.17 18.64c2.12 0 3.83 -1.73 3.83 -3.86c0 -2.13 -1.71 -3.85 -3.83 -3.85c-2.11 0 -3.82 1.72 -3.82 3.85s1.72 3.86 3.82 3.86zm-1.08 26.44l-40.3 -23.86l-0.79 1.36l40.28 23.87c1.85 1.11 4.23 0.5 5.33 -1.37l-1.34 -0.81c-0.66 1.12 -2.09 1.47 -3.19 0.81zm3.88 -17.91l-6.85 -4.03l-0.79 -10.34c-0.12 -1.24 -0.78 -2.35 -1.76 -3.03l-9.87 -5.89c-2.33 -1.58 -5.47 -0.96 -7.04 1.4c-0.86 1.29 -1.1 2.92 -0.68 4.24l2.68 8.84l-8.08 2.6c-1.01 0.41 -1.79 1.37 -1.93 2.54c-0.21 1.72 1.06 2.86 2.77 3.06c0.39 0.05 0.65 -0.07 1.01 -0.16l11.03 -3.68c0.81 -0.3 1.69 -1.11 1.78 -1.81c0.06 -0.51 0.23 -0.95 0.12 -1.25l-1.68 -6.05l6.63 3.98l0.8 5.8c0.07 1.01 0.53 1.74 1.3 2.18l8.67 5.11c0.95 0.53 2.15 0.17 2.67 -0.8c0.53 -0.96 0.17 -2.18 -0.78 -2.7z"/>
+</svg>