Adds recommendation to install poppler-data

* poppler-data seems to be required to extract text in a variety of encodings

Author: alindeman

index.html

@@ -130,7 +130,7 @@ <h2 id="installation">Installation &amp; Dependencies</h2>
       <li>
         Install <a href="http://poppler.freedesktop.org/">Poppler</a>.
         On Linux, use <b>aptitude</b>, <b>apt-get</b> or <b>yum</b>:<br />
-        <tt>aptitude install poppler-utils</tt><br />
+        <tt>aptitude install poppler-utils poppler-data</tt><br />
         On the Mac, you can install from source or use <b>MacPorts</b>:<br />
         <tt>sudo port install poppler | brew install poppler</tt><br />
       </li>