Refactor global variables for signal processing

These are:
	device, sample rate, buffer, latency
Called now:
	dsp_device, dsp_samplerate, dsp_buffer, dsp_latency
Call audio device:
	call_device, call_samplerate, call_buffer

src/zeitansage/main.c

@@ -93,7 +93,7 @@ int main(int argc, char *argv[])
 	fm_init(fast_math);
 	zeit_init(audio_level_dBm, alerting);
 
-	main_mobile("zeitansage", &quit, latency, interval, NULL, "1191", 4);
+	main_mobile("zeitansage", &quit, NULL, "1191", 4);
 
 //fail:
 	/* exits */