Enable use of logger for Notecard "debug

[gwolffblues]

I am limited in how I log Notecard debug information.
Using notecard.OpenSerial(port,debug=True) uses the Python native print function.

I would like the option to set the debug print function so I can provide my own debug logging function, or use one of the logging methods from the Python logging package.

That way I'm not restricted to recording debug information where print sends the message. But rather I can control how and where debug messages are stored and displayed.

Using print as the default is certainly fine.