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/water-tower.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 2,0 2,3.5 C 2,4.9469172 2.7905512,5.9802716 3.90625,6.625 L 3,14 4.5,14 4.6875,12.53125 7,11 9.3125,12.5625 9.5,14 11,14 10.09375,6.65625 C 11.21821,6.0132746 12,4.9628112 12,3.5 l 0,-3.5 -1.5,0 0,1.5 -0.5,0 C 8.8728814,2 8,2 7,1.5 6,1 5.0381356,1 4,1.5 l -0.5,0 0,-1.5 z m 3.34375,7.1875 c 1.069224,0.2671613 2.2426846,0.2935662 3.3125,0.03125 L 8.84375,8.78125 7,10 5.15625,8.78125 z m -0.3125,2.5 L 6.25,10.5 4.8125,11.46875 z m 3.9375,0 L 9.1875,11.46875 7.75,10.5 z"
+     id="water-tower"
+     style="fill:#000000;fill-opacity:1;stroke:none" />
+</svg>