Added RemoteStatus Class, StatusRequest Class, to allow for a call to 'getStatuses' to retrieve issue statuses

I believe I structured it correctly according to the way you set it up for the other *Remote's. `RemoteStatus` is only used once by the looks of it in the documentation, so maybe you don't want an empty class? But I figured you wouldn't want to have loads of bloat in `JiraClient.php` either.

Let me know if you'd rather it structured differently.