Fixed typo in

about.html

@@ -5,7 +5,7 @@
 
 <p>See full history on <a href="https://github.com/seblucas">Github</a> to check all authors.</p>
 
-<p>COPS use some external librairies, check README for the details.</p>
+<p>COPS use some external libriries, check README for the details.</p>
 <h2>Copyright</h2>
 <p>This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License version 2 as published by the Free Software Foundation.</p>
 
@@ -20,4 +20,4 @@
 <p>Thanks a lot to Kovid Goyal for <a href="http://calibre-ebook.com">Calibre</a>.</p>
 
 <p>And many thanks to all those who helped test COPS.</p>
-</div>
+</div>