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/table-tennis.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg id="table-tennis" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path id="icon_concepts:_sports_leisure" d="M11.9676,10.2275a3.8116,3.8116,0,0,1-1.9122.9831L3.7678,4.9338A4.0283,4.0283,0,0,1,4.7725,3.0324C7.03.7745,9.98.2235,12.3781,2.6219S14.2255,7.97,11.9676,10.2275Zm-6.987,1.6093A3.8422,3.8422,0,0,1,6.149,11.278,4.5328,4.5328,0,0,1,8,11.4452L3.5456,7a4.4126,4.4126,0,0,1,.1572,1.9223,3.6639,3.6639,0,0,1-.5208,1.1159c-1.072,1.263-2.132,1.727-2.132,2.1879A1.8378,1.8378,0,0,0,2.7739,13.95C3.2348,13.95,3.6917,12.9368,4.9806,11.8368Z"/>
+</svg>