Add inverted option.

Author: clemenshelm

server/documents/modules/popup.html.eco

@@ -684,6 +684,11 @@ themes      : ['Default']
           <td>10</td>
           <td>Number of iterations before giving up search for popup position when a popup cannot fit on screen</td>
         </tr>
+        <tr>
+          <td>inverted</td>
+          <td>false</td>
+          <td>Invert text and background colors</td>
+        </tr>
       </tbody>
     </table>