Upgrade from deprecated trio.Queue; fix tests; fix docs

[Zac-HD]

Closes #46.

Releasing a new version of trio-asyncio with this change will unblock python-trio/pytest-trio#68 - cc @njsmith

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@288abcb). Click here to learn what that means.
The diff coverage is 100%.

@@            Coverage Diff            @@
##             master      #49   +/-   ##
=========================================
  Coverage          ?   73.33%           
=========================================
  Files             ?       11           
  Lines             ?     1264           
  Branches          ?      165           
=========================================
  Hits              ?      927           
  Misses            ?      282           
  Partials          ?       55

Impacted Files	Coverage Δ
trio_asyncio/base.py	85.39% <100%> (ø)
trio_asyncio/async_.py	85% <100%> (ø)
trio_asyncio/sync.py	81.1% <100%> (ø)

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[Zac-HD]

Ping @smurfix - can you make a release soon to unblock pytest-trio? Thanks!

[pquentin]

Done: https://pypi.org/project/trio_asyncio/#history