* Fixed Issue #3, Added method `getUserRoles`, see `examples/get-user-roles.php`. Thanks [@openWebX](https://github.com/openWebX)
* Improved exception handling (on 403 errors, an `NotAuthorizedException` will be thrown)
* YouTrack-Exceptions are now `YouTrack\Error` aware (`$e->getYouTrackError()`)
* Small code formatting issues and removed redundant __construct()-methods