--play-pause command-line options don't work if player is in stop state

When player is in the stop state $exaile --play-pause changes the playback button icon from "play" to "pause". But playback doesn't start.

How to reproduce:
1. Open exaile.
2. Stop playback.
3. Run $exaile --play-pause.

What happens:
1. Icon changes (from play to pause) on playback button.

What should happen:
1. Icon changes (from play to pause) on playback button.
2. Playback actually start.

P.S. I hope that you agree that playback should start on --play-pause even if in stop state. But if not there is no need to chage icon on playback button.