Use logger instead of print calls

[wil93]

This would allow us to log more data than we do at the moment, e.g. in these two lines we inform of an error but we don't log the actual error:

mailipy/mailipy/send.py

Lines 43 to 44 in bdbeb9d

	except Exception:
	print("[!] Error when sending email to %s" % (msg["To"]))

By using logger we could have two calls, logger.error for the UI and logger.debug to log the actual exception