message: set dirty flag when programatically inserting text like with newlines
diff: @@ -175,6 +175,7 @@ export default class BasicMessageEditor extends React.Component {
  const newText = text.substr(0, caret.offset) + textToInsert + text.substr(caret.offset);
  caret.offset += textToInsert.length;
  this.props.model.update(newText, inputType, caret);
  + this._modifiedFlag = true;
  }
  // this is used later to see if we need to recalculate the caret
  