Library does not use logging

[paultiplady]

python-ach doesn't make any logs. This can make it hard to debug errors while developing, and to track down unexpected changes in production.

Would you accept PRs to gradually add logs using Python's loggers? These impose very little performance penalty, and can be set to default to WARN if you don't want to log by default.

Requests is an example of a library that makes very good use of logging. It's a single line in your application to disable their logger completely, but you can optionally get a lot of information about what's going on as well.