WIP: Add a script to output an mmdata.txt for FlexBV

[mmuman]

This generates the mmdata.txt file as required by FlexBV to gather measurements for the OpenBoardData project.

Currently the device and channel names are hardcoded in the script, ideally these would be configurables.

[mmuman]

I had a hard time getting it to terminate properly, first the stop button didn't really stop, just would complain about blocked SIGINT due to a race condition… Now it does stop, although each time the script is re-run, the number of times each line is printed on the console is increased by one. At least it doesn't assert anymore due to already running interpreter.