Use HC-06 default baud rate

The baud rate of 57600 was causing some stability issues. The ATtiny84's internal oscillator is too sensitive to the environment (mostly temperature) to use such a high rate. The default of 9600 should be just fine now that only one single byte is being sent for every byte received.

Additionally, the HC-06 did not always register the AT command to change baud rate, which was probably a timing issue. By using the default baud rate, we sidestep the issue of needing long boot times and a Bluetooth module reset to send that command.

I've left in, but commented out, the Bluetooth module reset code. It will be useful when adding the change-module-name functionality later.