Add references to Paperwork and Pyinsane

Ref: http://lists.alioth.debian.org/pipermail/sane-devel/2016-September/034778.html

sane-frontends.html

@@ -141,6 +141,12 @@
 	- a document imaging & archive project.
       </li>
 
+      <li>
+        <a href="https://github.com/jflesch/paperwork">Paperwork</a>
+        - a program to use scanners and OCR to grep dead trees the
+        easy way.  It uses the
+        <a href="https://github.com/jflesch/pyinsane">Pyinsane</a/>
+        Python binding to interface with SANE (and Windows WIA API).
     </ul>
 
     <h2>Graphical Frontends for Specific Devices</h2>