Add tooltip viewport option, respect bounds of the viewport

docs/javascript.html

@@ -1027,6 +1027,22 @@ $('#example').tooltip(options)
             <p>Appends the tooltip to a specific element. Example: <code>container: 'body'</code></p>
            </td>
          </tr>
+         <tr>
+           <td>viewport</td>
+           <td>string</td>
+           <td>'body'</td>
+           <td>
+            <p>Keeps the tooltip within the bounds of this element. Example: <code>viewport: '#viewport'</code></p>
+           </td>
+         </tr>
+         <tr>
+           <td>viewportPadding</td>
+           <td>number</td>
+           <td>0</td>
+           <td>
+            <p>Pixel distance to keep the tooltip from the edges of the viewport element. Example: <code>viewportPadding: 10</code></p>
+           </td>
+         </tr>
         </tbody>
       </table>
     </div><!-- /.table-responsive -->