Added links to downloadable docs in the docs

docs/_templates/sidebarintro.html

@@ -5,6 +5,11 @@
   not stable yet, but if you have some feedback,
   <a href="mailto:armin.ronacher@active-4.com">let me know</a>.
 </p>
+<h3>Download Documentation</h3>
+<ul>
+  <li><a href="http://flask.pocoo.org/docs/flask-docs.pdf">as PDF</a>
+  <li><a href="http://flask.pocoo.org/docs/flask-docs.zip">as zipped HTML</a>
+</ul>
 <h3>Useful Links</h3>
 <ul>
   <li><a href="http://flask.pocoo.org/">The Flask Website</a></li>