add blinking colon by seconds

LibreMetric.ino

@@ -120,8 +120,9 @@ void loop() {
   //Serial.println(time);
   time.trim();
   time.substring(11,19).toCharArray(time_value, 10);
+  int seconds = time.substring(17,19).toInt();
   for (int i = 0; i <= 4; i++) {
-    matrix.drawChar(i*6+2,0, time_value[i], HIGH,LOW,1); // H
+    matrix.drawChar(i*6+2,0, (i==2 && seconds %2) ?  char(0x20): time_value[i], HIGH,LOW,1); // H
   }
   matrix.write(); // Send bitmap to display
   if (message != "") {