Set error if GET_SIGN_ON not followed by CRC_EOP

Author: Randall Bohn (Huckle)

build/shared/examples/11.ArduinoISP/ArduinoISP/ArduinoISP.ino

@@ -497,6 +497,10 @@ int avrisp() {
         Serial.print("AVR ISP");
         Serial.print((char) STK_OK);
       }
+      else {
+        error++;
+        Serial.print((char) STK_NOSYNC);
+      }
       break;
     case 'A':
       get_version(getch());
@@ -574,5 +578,3 @@ int avrisp() {
   }
 }
 
-
-