Add Python logging with same format as Java

[cbornet]

Fix #346

[nicoloboschi]

How the custom processor should call the logger?

[cbornet]

The processor can use logging.info or it's own logger. Eg:

import logging
logging.info("hello") # uses the root logger

LOG = logging.getLogger(__name__) # uses a logger with the module name
LOG.info("world")

[eolivelli]

+1

we need to add a section to the docs here

[cbornet]

we need to add a section to the docs here

Sure. Note that logging is built-in in Python. So there is no surprise here for Python devs.