Most of the time people want to pause playback, rather than stop
entirely. Let's remove the button since it's not getting any use.
Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>
This is better than calling audio_*() functions directly, since we can
make sure signals are wired up properly in glade.
Signed-off-by: Anna Schumaker <Anna@OcarinaProject.net>