Code quality improvements

[levino]

See https://github.com/figo-connect/node-figo/blob/master/lib/figo.js#L115 and following:

Currently (wrong):

if (this.statusCode === 401) {
  callback(new FigoError("unauthorized", "Missing, invalid or expired access token."));
} else if (this.statusCode === 403) {
  callback(new FigoError("forbidden", "Insufficient permission."));
} else if (this.statusCode === 404) {
  callback(null, null);
} else if (this.statusCode === 405) {
  callback(new FigoError("method_not_allowed", "Unexpected request method."));
} else if (this.statusCode === 503) {
  callback(new FigoError("service_unavailable", "Exceeded rate limit."));
} else {
  callback(new FigoError("internal_server_error", "We are very sorry, but something went wrong."));
}

Better:

if (this.statusCode === 401) {
  return callback(new FigoError("unauthorized", "Missing, invalid or expired access token."));
}
if (this.statusCode === 403) {
  return callback(new FigoError("forbidden", "Insufficient permission."));
}
if (this.statusCode === 404) {
  return callback(null, null);
}
if (this.statusCode === 405) {
  return callback(new FigoError("method_not_allowed", "Unexpected request method."));
}
if (this.statusCode === 503) {
  return callback(new FigoError("service_unavailable", "Exceeded rate limit."));
}
return callback(new FigoError("internal_server_error", "We are very sorry, but something went wrong."));

See also:

http://nodeguide.com/style.html#return-statements

[JeremyCraigMartinez]

Issue resolved: 5cffdbd