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/planes_bidirectional.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="M8.19 0.83C8.66 1.3 8.43 2.01 7.49 2.95L7.13 3.3L7.49 7.19L6.78 7.9L5.36 5.07L3.95 6.49L3.95 7.9L3.24 8.61L2.54 6.49L0.41 5.78L1.12 5.07L2.54 5.07L3.95 3.66L1.12 2.24L1.83 1.54L5.72 1.89L6.07 1.54C7.01 0.59 7.72 0.36 8.19 0.83ZM6.83 14.19C6.36 13.72 6.59 13.01 7.54 12.07L7.89 11.72L7.54 7.83L8.24 7.12L9.66 9.95L11.07 8.54L11.07 7.12L11.78 6.41L12.49 8.54L14.61 9.24L13.9 9.95L12.49 9.95L11.07 11.36L13.9 12.78L13.19 13.49L9.3 13.13L8.95 13.49C8.01 14.43 7.3 14.66 6.83 14.19Z"/>
+</svg>