Why include db.py

[matthijskooijman]

I've been looking at this package as a convenient way to output measurements to telegraf. It looks like the intent of this package is to write a python script that is called by telegraf's exec plugin, so it just needs to handle printing the telegraf format.

However, there also seems to be a db.py that has two seemingly unrelated utilities for extracting data from mysql and postgresql datasets. Not a big deal in itself, but this does add dependencies on extra database-related python packages, but also e.g. the libpg package, making telegraf_pyplug a lot less suitable for a quick standalone python script.

I can imagine it is convenient to have these database helpers in this package that you're already including anyway, but maybe it would make sense to put these helpers in their own package and leaving this package for just the telegraf-related code?