asyncio Event loop policy, UnicodeEncodeError and planners' exception handling (fixes #3)

[Voyz]

fixes #3

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Fixes or warns against two errors that can occur on Windows :

• UnicodeEncodeError - if default stdin/stdout encoding is unusual (for instance windows-1252)
• Asyncio/Event loop is closed - if run on Python 3.8+

Also fixes exception handling of unusual exceptions on both APSPlanner and SchedulePlanner.

@pybokeh if you like give this a quick look through - this fixes the issue #3 we've been discussing over the last week.

(This PR additionally contains small tweaks that were found in #3 and a unit test for config.py)

[pybokeh]

I'm no expert, but these fixes look good to me. I see that you did look into that syntax warning that I was seeing intermittently.
Hopefully, only a few other Windows users will have unusual setups like mine ;-)

I'm sure you'll be able to attract more experienced contributors to this project and I will definitely advertise! Since this project has extensibility designed in, I hope to see more outlets made. I look forward to someone creating a PostgreSQL outlet some day. It is very refreshing to see a Python library with a producer-consumer paradigm that also works on Windows.

Thank you for your kind and quick responses!

[Voyz]

Great, thanks for the review @pybokeh! Indeed, got that print syntax issue fixed. I'd love to indeed see what you describe - a library of various inlets and outlets being shared amongst the community. I went ahead with some functionalities I felt comfortable with, although by no means could I implement all the common use cases, so hoping that some developers will pick up the ball and help me keep it rolling. PostgreSQL for instance I wouldn't be competent enough with implementing. Will ping you if someone does one day though!

Going ahead with a merge for this PR and will follow with a new release soon after.

Thanks for collaborating and hope to speak to you again sometime :)
Voy