avoid redirect stdout and stderr for robot

[jupe]

Currently all stdout/stderr is redirected to keyword results outputs during keyword execution which leads that some logs flows to robot remote server process stdout and some to robot framework test/KW logs. This makes very hard to debug remote server instance. Propose to utilise logging module so that during keyword we just create custom logging handler that collects keywords logs for robot framework but allows simultaneous log everything to stdout/stderr in server process.

I had to create workaround while debugging one issue form remote server side: https://github.com/jupe/PythonRemoteServer/pull/1 .

I think generally stdout/stderr redirecting like this is not very good approach for library side..

[pekkaklarck]

RoboCon sprints are running today and we just decided to talk about Python remote servers there at 12:00 UTC. Sprints are organized on Gather and you can access them via https://venue.robocon.io. This is very late notice but it would be great if you could make it there @jupe!