Run jekyll as part of the matrix-doc build

- this saves us having to run it manually on the web server.

scripts/add_anchors.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python
+#
+# adds anchors before any <h1/h2/h3/h4/h5> tags with an id="..." - this is used
+# for things like the FAQ where we want to have anchored links to every
+# question (and this way you don't have to manually maintain it in the source
+# doc).
+
+from sys import argv
+import re
+
+script, filename = argv
+
+textfile = open(filename, "r")
+regex = r'(<h\d id="(.*?)">)'
+regex2 = r'(<div class="section" id="(.*?)">)'
+
+replacement = r'<p><a class="anchor" id="\2"></a></p>\n\1'
+
+# check for <hX id="..." (used in the FAQ) and add anchors - and then check
+# for <div class="section" id="..." and add anchors (used in the spec)
+for line in textfile:
+  line = re.sub(regex, replacement, line.rstrip())
+  print(re.sub(regex2, replacement, line.rstrip()))