function APIError(message, code) {
  Error.call(this);
  Error.captureStackTrace(this, arguments.callee);
  this.name = 'APIError';
  this.message = message;
  this.code = code;
  this.status = 500;
}
`APIError` error.

References:
  - https://dev.twitter.com/overview/api/response-codes

@constructor
@param {string} [message]
@param {number} [code]
@access public