Remove debug console output in Python data processing library functionality

[rtrueb]

It would be helpful if the printout of the merge_channels function could be disabled (either permanently, via state of the RocketLoggerData class, or via a function argument).

[lsigrist]

Thanks @rtrueb, this is a very good point. It is probably not the task of a data processing library to print to the console what it is doing. I'd even extend your input to any print statement in rocketlogger.data (see list below) and rather make sure that relevant warnings/errors are raised for unexpected behavior/failures. What do you think? Does this match your reasons for raising this issue?

• #772 - drop, this is expected user defined behavior (function arguement)
• #924 - drop, more of a debug output for expected result
• #1190 - drop, more of a debug output for expected result

[rtrueb]

The proposed changes address my issue and make sense from my point of view.

[lsigrist]

fix verified using a942b32