Prevent problems after 49 days in model 3

[RainerWinkler]

Handle the rollover of millis() in model 3 correctly. As for instance described here: https://www.baldengineer.com/arduino-how-do-you-reset-millis.html

[RainerWinkler]

The fix has to assure that the rollover works correctly. To do this do not use millis() directly but add a very high value to millis() and use this value. Do this in a way that the rollover takes place about a minute after starting the program. Any errors due to the rollover will than occur immidiately after start. This will lead to a good test coverage of the rollover.