Fix typos in documents and comments

Fix typos detected by toolkit misspellings.

* pip install misspellings
* git ls-files | grep -v locale | misspellings -f -

Change-Id: If986f8cfefae08089caa567618dbb13bff0d62d2
Cleanup eventlet setup

Since environment.use_eventlet() is done in test/core.py, no need
to also do it in fixtures/appserver.py

Change-Id: I1bb4ebbca7a423ab30d945745e092cadf8817da6
Merge "Fix typos in documents and comments"
Merge "Cleanup eventlet setup"