Add more WD feed and flags check to save loop time

remove PURE_SERIAL define as useless now

esp3d/command.cpp

@@ -493,6 +493,14 @@ bool COMMAND::check_command(String buffer, tpipe output, bool handlelockserial)
     bool is_temp = false;
     //feed the WD for safety
     delay(0);
+#if ((FIRMWARE_TARGET == REPETIER) || (FIRMWARE_TARGET == REPETIER4DV))
+    //save time no need to continue
+    if ((buffer.indexOf("busy:") > -1) || (buffer.startsWith("wait")))return false;
+#endif
+    //because some answer start by ok ...
+#if (FIRMWARE_TARGET != SMOOTHIEWARE)
+    if (buffer.startsWith("ok"))return false;
+#endif
 //if direct access to SDCard no need to handle the M20 command answer
 #ifndef DIRECT_SDCARD_FEATURE
     static bool bfileslist=false;