EntryPoint() is not comparable, so convert to string and sort those instead.
We only need the string anyway.

Update the complex-dist/setup.py to have multiple entrypoints, though I
didn't see anything in the test that verifies that all of the entrypoints
were successful.

use split instead of rsplit to create abi_tag from SOABI

turns 'cpython-35m-darwin' into 'cp35m'

SOABI is cpython-35m-darwin on CPython 3.5 on OS X.
rsplit produces `cpdarwin`, whereas split produces the desired `cp35m-darwin`.

Fix typo in CHANGES.txt