rotate(angle, isSilent) {
    return this._rotate('rotate', angle, isSilent);
  }
Rotate image
@returns {Promise}
@param {number} angle - Additional angle to rotate image
@param {boolean} isSilent - is silent execution or not
@returns {Promise<RotateStatus, ErrorMsg>}
@example
imageEditor.rotate(10); // angle = 10
imageEditor.rotate(10); // angle = 20
imageEditor.rotate(5); // angle = 5
imageEditor.rotate(-95); // angle = -90
imageEditor.rotate(10).then(status => {
    console.log('angle: ', status.angle);
})).catch(message => {
    console.log('error: ', message);
});