Bug 49117 [Plan Item] Workbench needs hooks for new welcome support
M6 We need to provide an extension point and some interfaces to allow for a primary feature to declare a welcome page. This extension point will be tied the new IProduct being defined by the Core team and needs to have 3 states 1) Fill whole screen 2) Collapsed on the right when the user selects something and starts working 3) Disables when it is no longer of any use
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/ide/IDEWorkbenchAdvisor.java
* @see org.eclipse.ui.application.WorkbenchAdvisor#postShutdown
	 */
	public void postShutdown() {
		if (activityHelper != null) {
			activityHelper.shutdown();
			activityHelper = null;
		}
		if (IDEWorkbenchPlugin.getPluginWorkspace() != null) {
			disconnectFromWorkspace();
		}
	}
	/* (non-Javadoc)
	 * @see org.eclipse.ui.application.WorkbenchAdvisor#eventLoopException
	 */
	public void eventLoopException(Throwable exception) {
		super.eventLoopException(exception);
		if (exceptionHandler != null) {
			exceptionHandler.handleException(exception);
		} else {
			if (configurer != null) {
				configurer.emergencyClose();
			}
		}
	}
	/* (non-Javadoc)
	 * @see org.eclipse.ui.application.WorkbenchAdvisor#preWindowShellClose
	 */
	public boolean preWindowShellClose(IWorkbenchWindowConfigurer windowConfigurer) {
		if (configurer.getWorkbench().getWorkbenchWindowCount() > 1) {
			return true;