Breaking changes
`PlexClient.timeline()` previously returned a raw XML object. Now returns a newly available `ClientTimeline` instance for the current active session. See 572.
New Features
* 507 - Edit Library and Show's Advanced Settings
* 518 - Library Hubs and Music Stations
* 582 - Add download feature to Photo library
* 572 - Update timeline to return an active timeline object w/ attributes
* 585 - Allow scanning for clients when using GDM.all()
* 592 - Make Photo objects Playable
Bug fixes
* 580 - Add server handling of HTTP status code 204
* 581 - Handle empty datetimes in tests
* 583 - Updating cleanBundles() and optimize() methods
* 588 - Collection fields not pulling locked fields
* 594 - Don't overwrite existing attributes with an empty list