QoL improvements / hotkeys
QoL improvements / hotkeys

- Allow control of volume via hotkeys
- Allow seek via hotkeys
- Replaced deprecated "which" with "code"/"key" for hotkeys

Hotkeys added:
- Up: Increase volume (5 / 20 %)
- Down: Decrease volume (5 / 20 %)
- M: Mute toggle
- J: Seek forward (5 / 30 sec)
- L: Seek backwards (5 / 30 sec)
- K: Alias for Space (Play/Pause)
- Shift+Period / Shift+>: Increase playback speed
- Shift+Comma / Shift+<: Decrease playback speed

paulijar/music,paulijar/music,owncloud/music,paulijar/music,owncloud/music,paulijar/music,paulijar/music,owncloud/music,owncloud/music,owncloud/music