message: Make both icon and label optional in Dialog.Button
diff: @@ -277,12 +277,12 @@ declare namespace Dialog {
  /**
  * A Font Awesome icon for the button
  */
  - icon: string;
  + icon?: string;
  /**
  * The label for the button
  */
  - label: string;
  + label?: string;
  /**
  * A callback function that fires when the button is clicked
  