Improve loop handling

[balloob]

This improves loop handling for HAP-Python:

• Do not change the default executor of passed in loops
• Do not shut down loops/executor pools that were passed in

[codecov-commenter]

Codecov Report

Merging #270 into dev will decrease coverage by 0.37%.
The diff coverage is 72.22%.

@@            Coverage Diff             @@
##              dev     #270      +/-   ##
==========================================
- Coverage   64.50%   64.13%   -0.38%     
==========================================
  Files          16       16              
  Lines        1761     1751      -10     
  Branches      189      191       +2     
==========================================
- Hits         1136     1123      -13     
- Misses        572      573       +1     
- Partials       53       55       +2     

Impacted Files	Coverage Δ
pyhap/accessory_driver.py	69.28% <72.22%> (-0.79%)	⬇️
pyhap/accessory.py	56.16% <0.00%> (-0.60%)	⬇️
pyhap/camera.py	77.20% <0.00%> (-0.25%)	⬇️
pyhap/loader.py	90.00% <0.00%> (-0.25%)	⬇️
pyhap/hap_server.py	38.65% <0.00%> (-0.13%)	⬇️
pyhap/service.py	98.11% <0.00%> (-0.04%)	⬇️
pyhap/state.py	100.00% <0.00%> (ø)
pyhap/encoder.py	100.00% <0.00%> (ø)
pyhap/characteristic.py	100.00% <0.00%> (ø)

[bdraco]

            if threading.current_thread() is threading.main_thread():
                logger.debug('Setting child watcher')
                watcher = asyncio.SafeChildWatcher()
                watcher.attach_loop(self.loop)
                asyncio.set_child_watcher(watcher)

I think we need a way to call _do_start without the above in start

[balloob]

Done, renamed _do_start to start_service

[bdraco]

Everything appears to work as expected in the linked PR (testing using the existing protected methods)

[bdraco]

travis is happy
https://travis-ci.org/github/ikalchev/HAP-python/builds/704797505

[balloob]

This change is breaking Python 3.5 support. It's not necessary, just a drive by cleanup from when I saw warnings printed during tests. I will revert it.

[bdraco]

Verified working with home-assistant/core#37441

[bdraco]

Verified this doesn't regress busy home example

[bdraco]

@ikalchev If this one looks good, could we get a new release?

Thank you.

[ikalchev]

Change is good, will release in the evening.

Best,
Ivan

[bdraco]

Thanks Ivan 👍