add comments & and a TODO

TODO

@@ -0,0 +1,4 @@
+- in squeezelite some buffers (stream, output, header, recv) are allocated 
+although they are almost static (expect output). This creates a risk of 
+memory fragmentation, especially because the large output is re-allocated for
+AirPlay

components/squeezelite/decode_external.c

@@ -213,6 +213,7 @@ void raop_sink_cmd_handler(raop_event_t event, void *param)
 			break;
 		}
 		case RAOP_SETUP:
+			// we need a fair bit of space for RTP process
 			_buf_resize(outputbuf, RAOP_OUTPUT_SIZE);
 			LOG_INFO("resizing buffer %u", outputbuf->size);
 			break;