Not able to enter programming mode on EMH meter - serial transport

[Krolken]

After checking some errors reported by users, #4 I found that it is not possible to enter programming mode on an EMH meter.

A quick look suggests it is a combined error of the ASCII representation of a command and that we are not preforming a baudrate switch that the meter proposes. (Or telling the meter that we want to stay at our current baudrate.)

The baudrate issue is only contained to the serial transport as it doesn't have effect on the TCP transport. But the client still needs to call the switch for both of the transport to work.