Play/pause button does not change when stop button pressed

[rrlapointe]

The play/pause button toggles between displaying the "play" symbol and the "pause" symbol when pressed. When the stop button is pressed, it should change to display the "play" symbol.

[SamCarlberg]

These controls really just need an overhaul.

Playback controls shouldn't be visible when not in playback mode, and recording controls shouldn't be visible during playback.