Enhanced comments in asynnet

Changed required privilege for chnaging the threshold from manager to user in counter.c
Changed an output code in macro.c

asynnet.c

@@ -338,7 +338,12 @@ static int anetTestWrite(SocketDescriptor con)
   }
   return 1;
 }
-/*--------------------------------------------------------------------------*/
+/*--------------------------------------------------------------------------
+  There is something implicit in the return here: anetRead must return 0 
+  when the list of sockets changes. Otherwise ANETprocess cannot detect that it has 
+  an invalid socket list and jump out. In all other cases anetRead must return 1
+-------------------------------------------------------------------------------*/   
+
 static int anetRead(SocketDescriptor con)
 {
   int socke, handle, status;