mpris: Correcting get_CanGoPrevious to get() the future instead of passing it.
The failure was invisible to testcases
docs: Documenting further the TracklistController functions
tests: tracklist tests renaming the TracklistController holder from controller to tracklist for test uniformity
Merge branch 'tidy-up-core' into tracklist-provider
tests: moving more tests from playback to tracklist
Merge branch 'tidy-up-core' into tracklist-provider