Soco

- Add 'seek_back' action to jump back within a track
- Action 'seek' now supports more flexible time formats
- Add 'seek_to' synonym for 'seek'
- Improve 'track' output when reporting a stopped stream
- Add 'min_netmask' option for alternative discovery
- Improve network selection logic when using alternative discovery
- Improve network timeout logic when using alternative discovery

- Fix WARN(ING) setting for --log option
- Require SoCo >= 0.20

- Add search caching and indexed playback for 'list_albums'
- Add search caching and indexed playback for 'search_artists'
- Add '--docs' option to print URL to online documentation
- Add 'soco-discover' synonym for 'sonos-discover'
- Add line_in 'right_input' parameter for stereo paired P:5/Fives
- Behaviour change: Line-In starts playback after being selected

- Improve output from 'track' action for non-queue items
- Add 'cue_favourite_radio_station' action

- Add 'queue_last_search_number' action

- Add 'play_next' option to 'queue_track' and 'queue_album'
- Add 'play_next' option for 'add_playlist_to_queue'
- Add 'play_next' option for 'add_favourite_to_queue'