Let OpenAL autodetect sound device.

--- a/sound/sound.pyx
+++ b/sound/sound.pyx
@@ -70,7 +70,7 @@
 	cdef int attrs[6]
 	if _SOUND_INITED == 0:
 		
-		_device = alcOpenDevice(PyString_AS_STRING(device_names))
+		_device = alcOpenDevice(NULL)
 		
 		if _device == NULL:
 			raise RuntimeError("Cannot create an OpenAL device!")
