audio_output: added method pause()

pause() puts the audio output into pause mode: if supported, it may
perform a special action, which keeps the device open, but does not
play anything.  Output plugins like "shout" might want to play silence
during pause, so their clients won't be disconnected.  Plugins which
do not support pausing will simply be closed, and have to be reopened
when unpaused.

This pach includes an implementation for the shout plugin, which
sends silence chunks.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/audio.h b/src/audio.h
index 4e34b0f61..3ffa2dc55 100644
--- a/src/audio.h
+++ b/src/audio.h
@@ -45,6 +45,8 @@ int openAudioDevice(const struct audio_format *audioFormat);
 
 int playAudio(const char *playChunk, size_t size);
 
+void audio_output_pause_all(void);
+
 void dropBufferedAudio(void);
 
 void closeAudioDevice(void);