Stop using SIGUSR1 for cancelling threads, use pthread_cancel and friends instead, fix some memory leaks, add accurate ouput rate calculation to statistics, add "quit" verb to MPRIS and native d-bus interfaces. Probably still buggy.

audio_ao.c

@@ -121,7 +121,7 @@ static void deinit(void) {
 static void start(__attribute__((unused)) int sample_rate,
                   __attribute__((unused)) int sample_format) {}
 
-static void play(void *buf, int samples) { ao_play(dev, buf, samples * 4); }
+static int play(void *buf, int samples) { return ao_play(dev, buf, samples * 4); }
 
 static void stop(void) {}