#6 Autobaud support

[Philipp Klaus Krause]

When setting up a port, in addition to the list of fixed baud rates , there should be an "Auto" option, which uses automatic baud rate detection (see e.g. https://en.wikipedia.org/wiki/Automatic_baud_rate_detection). The wikipedia page mentions 0x61 and 0x41 as common autobaud characters, but in my experience, today, 0x55 is more common, so all three should work.