Added --param low-latency-audio

Currently modifies these values these values:
* audio pbuf delay - 32 ms -> 5 ms
* ALSA playback - minimal value
* ALSA audio buffer (internal in UG module) - 20 ms -> 5 ms
* audio mixer, internal audio buffer - 50 ms -> 5 ms

src/host.cpp

@@ -328,6 +328,9 @@ void print_param_doc()
         }
 }
 
+// some common parameters used within multiple modules
+ADD_TO_PARAM_DOC(low_latency_audio, "* low-latency-audio\n"
+                "  Try to reduce audio latency at the expense of worse reliability\n");
 ADD_TO_PARAM_DOC(ldgm_device, "* window-title=<title>\n"
                 "  Use alternative window title (SDL/GL only)\n");