Remove USB Serial.begin 2.5 second wait for connection

teensy3/usb_serial.h

@@ -74,15 +74,16 @@ public:
 	constexpr usb_serial_class() {}
         void begin(long) {
 		uint32_t millis_begin = systick_millis_count;
-		while (!(*this)) {
+		//disabled for now - causes more trouble than it solves?
+		//while (!(*this)) {
 			// wait up to 2.5 seconds for Arduino Serial Monitor
 			// Yes, this is a long time, but some Windows systems open
 			// the port very slowly.  This wait allows programs for
 			// Arduino Uno to "just work" (without forcing a reboot when
 			// the port is opened), and when no PC is connected the user's
 			// sketch still gets to run normally after this wait time.
-			if ((uint32_t)(systick_millis_count - millis_begin) > 2500) break;
-		}
+			//if ((uint32_t)(systick_millis_count - millis_begin) > 2500) break;
+		//}
 	}
         void end() { /* TODO: flush output and shut down USB port */ };
         virtual int available() { return usb_serial_available(); }