Playback tool bar UI

The playback toolbar has been downgraded from version 3.x and some of the common options have been placed in the playback settings menu. Since the Play Panel no longer exists its functionality should be accessible from the playback toolbar.

All the following buttons should be on the playback toolbar. * indicates those that are not available:
* 1 - Docking dock/undock icon to drag
2- Back - Forward - * Beginning arrows
3 - Loop
* 4 - Repeat toggle on/off
* 5 - Pan toggle on/off (currently in settings)
6 - Metronome
* 7 - Chords toggle on/off (currently in settings)
* 8 - Volume change
* 9 - Tempo change (currently in settings)
* 10 - Midi toggle (currently in settings)
11 - Settings
| - Separator
12 - Playback timer
13 - Playback measure:note
14 - Tempo