new timout/add adv_ok

Marlin/Configuration_adv.h

 #define MAX_CMD_SIZE 96
 #define BUFSIZE 4
 
-// Some Hosts doesn't have a timeout for resend a command.
-// This is a workaround for them. If your printer sometimes stuck and stop printing this could help.
-// #define NO_TIMEOUTS
+// Bad Serial-connections can miss a received command by sending an 'ok'
+// Therefore some clients go after 30 seconds in a timeout. Some other clients start sending commands while receiving a 'wait'.
+// This wait is only send when the buffer is empty. The timeout-length is in milliseconds. 1000 is a good value.
+// #define NO_TIMEOUTS 1000
+
+// Some clients will have this feature soon. This should make the NO_TIMEOUTS unnecessary.
+// #define ADVANCED_OK
 
 // @section fwretract
 

Marlin/Marlin_main.cpp

     static millis_t last_command_time = 0;
     millis_t ms = millis();
   
-    if (!MYSERIAL.available() && commands_in_queue == 0 && ms - last_command_time > 1000) {
+    if (!MYSERIAL.available() && commands_in_queue == 0 && ms - last_command_time > NO_TIMEOUTS) {
       SERIAL_ECHOLNPGM(MSG_WAIT);
       last_command_time = ms;
     }
   #ifdef SDSUPPORT
     if (fromsd[cmd_queue_index_r]) return;
   #endif
-  SERIAL_PROTOCOLLNPGM(MSG_OK);
+  SERIAL_PROTOCOLPGM(MSG_OK);
+  #ifdef ADVANCED_OK
+    SERIAL_PROTOCOLPGM(" N"); SERIAL_PROTOCOL(gcode_LastN);
+    SERIAL_PROTOCOLPGM(" S"); SERIAL_PROTOCOLLN(commands_in_queue);
+  #endif
 }
 
 void get_coordinates() {