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/osmic/metro.svg

@@ -0,0 +1,40 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created with Inkscape (http://www.inkscape.org/) -->
+
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   version="1.1"
+   width="100%"
+   height="100%"
+   viewBox="0 0 14 14"
+   id="svg2">
+  <metadata
+     id="metadata8">
+    <rdf:RDF>
+      <cc:Work
+         rdf:about="">
+        <dc:format>image/svg+xml</dc:format>
+        <dc:type
+           rdf:resource="http://purl.org/dc/dcmitype/StillImage" />
+        <dc:title></dc:title>
+      </cc:Work>
+    </rdf:RDF>
+  </metadata>
+  <defs
+     id="defs6" />
+  <rect
+     width="14"
+     height="14"
+     x="0"
+     y="0"
+     id="canvas"
+     style="fill:none;stroke:none;visibility:hidden" />
+  <path
+     d="M 7,0 C 0,0 0,6 0,7 l 0,5 3,0 -1,2 3,0 1,-2 2,0 1,2 3,0 -1,-2 3,0 0,-5 C 14,6 14,0 7,0 z m -3,2 6,0 2,2 0,5 c 0,0.576271 -0.389831,1 -1,1 L 3,10 C 2.457627,10 2,9.576271 2,9 L 2,4 4,2 z M 5,3 C 4,3 3,4 3,5 l 0,2 8,0 0,-2 C 11,4 10,3 9,3 L 5,3 z M 3.75,7.75 C 3.335786,7.75 3,8.085786 3,8.5 3,8.914214 3.335786,9.25 3.75,9.25 4.164214,9.25 4.5,8.914214 4.5,8.5 4.5,8.085786 4.164214,7.75 3.75,7.75 z m 6.5,0 C 9.835787,7.75 9.5,8.085786 9.5,8.5 9.5,8.914214 9.835787,9.25 10.25,9.25 10.664213,9.25 11,8.914214 11,8.5 11,8.085786 10.664213,7.75 10.25,7.75 z"
+     id="metro"
+     style="fill:#000000;fill-opacity:1;stroke:none" />
+</svg>