Bug 54347 [Dialogs] Provide "Yes No Always Never" dialog
In Debug UI, we define a dialog that prompts the user to answer Yes, No, Always, or Never. If anyone's interested, this code is generic and could be shipped as a JFace component. The dialog is in the org.eclipse.debug.ui project; the type name is AlwaysNeverDialog. The dialog supports passing in a preference store and preference key for the dialog to persist an Always or Never selection. For cases where clients don't have a preference store but still want to be able to get at the user's response, it alternatively supports passing in a string buffer where the dialog will store the "always/never/prompt" status.
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/MessageDialog.java
* Image, or <code>null</code> if none.
	 */
	private Image image = null;
	
	/**
	 * The custom dialog area.
	 */
	private Control customArea;
/**
 * Create a message dialog.
 * Note that the dialog will have no visual representation (no widgets)
 * until it is told to open.
 * <p>
 * The labels of the buttons to appear in the button bar are supplied in this
 * constructor as an array. The <code>open</code> method will return the index
 * of the label in this array corresponding to the button that was pressed to 
 * close the dialog. If the dialog was dismissed without pressing a button (ESC, etc.)
 * then -1 is returned. Note that the <code>open</code> method blocks.
 * </p>
 *
 * @param parentShell the parent shell
 * @param dialogTitle the dialog title, or <code>null</code> if none
 * @param dialogTitleImage the dialog title image, or <code>null</code> if none
 * @param dialogMessage the dialog message
 * @param dialogImageType one of the following values:
 * <ul>
 *	<li> <code>MessageDialog.NONE</code> for a dialog with no image </li>
 *	<li> <code>MessageDialog.ERROR</code> for a dialog with an error image </li>
 *	<li> <code>MessageDialog.INFORMATION</code> for a dialog with an information image </li>
 * 	<li> <code>MessageDialog.QUESTION </code> for a dialog with a question image </li>