Bug 168304 Context root issue when set to other BIRT Web Project.[0603]
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/servlet/ViewerServlet.java
* <td>required</td>
 * </tr>
 * <tr>
 * <td>__format</td>
 * <td>The output format</td>
 * <td>html or pdf</td>
 * <td>optional, default to html</td>
 * </tr>
 * <tr>
 * <td>__locale</td>
 * <td>Report locale</td>
 * <td>Java locale value such as en or ch-zh.</td>
 * <td>optional, default to JVM locale</td>
 * </tr>
 * <tr>
 * <td>__page</td>
 * <td>Report page number</td>
 * <td>Report page to be viewed.</td>
 * <td>optional, default to 0</td>
 * </tr>
 * <tr>
 * <td><i>reportParam</i></td>
 * <td>User defined report parameter.</td>
 * <td>As specified in the report design.</td>
 * <td>As specified in the report design.</td>
 * </tr>
 * </table>
 * <p>
 */
public class ViewerServlet extends BirtSoapMessageDispatcherServlet