message: Allow BaseDialog to take a class for the title <div>
  Some dialogs need to set additional classes on the `mx_Dialog_title` `div`
  element (for example `danger`).
diff: @@ -75,7 +75,7 @@ export default React.createClass({
  >
  <TintableSvg src="img/icons-close-button.svg" width="35" height="35" />
  </AccessibleButton>
  - <div className='mx_Dialog_title'>
  + <div className={'mx_Dialog_title ' + this.props.titleClass}>
  { this.props.title }
  </div>
  { this.props.children }
  