'title' mpv option does not work

[ejkarne]

Overview Description: Using the 'title' mpv option has no effect on the title used by gnome-mpv.

Steps to Reproduce:

1. Add --title='${media-title} - ${width} ${height}' to the extra mpv options.

Actual Results: gnome-mpv ignores the title we set and just uses the media title.

Expected Results: gnome-mpv should pick up the 'title' mpv option and set the title accordingly.

Version: 0.22.0

Additional Information: OS: Solus 2017.01.01.0 shannon

[gnome-mpv]

There is no straightforward way to implement this yet due to the lack of API to perform property expansion.

https://github.com/mpv-player/mpv/issues/3166

[gnome-mpv]

mpv added support for performing property expansion via the expand-text command, so it's possible to implement this now.