In `CloseableQueue.py`, the imports are now wrapped in a try/except
block.  The new Python 3 imports are done in the `try` clause and the
original Python 2 imports are left intact under the `except` clause.

To update the tests, used a [recent version of test_queue.py][1] as a
reference to find out how the mainline copy evolved since the creation
of CloseableQueue.  I integrated the changes that allowed the test
cases to run without crashing.

[1]: https://github.com/python/cpython/blob/v3.7.2/Lib/test/test_queue.py

In `CloseableQueue.py`, replace `raise StopIteration` with `return`,
since [these are equivalent][1].  The deprecation is related to [PEP
479][2].

In the tests, `assertEquals` and `assert_` were replaced with
`assertEqual` and `assertTrue`, respectively.  The old names were
[deprecated in Python 3.2][3].

[1]: https://docs.python.org/2/reference/simple_stmts.html#the-return-statement
[2]: https://www.python.org/dev/peps/pep-0479/
[3]: https://docs.python.org/3/library/unittest.html?highlight=unittest#deprecated-aliases

Python 3 compatibility

This repository now contains a package known as CloseableQueue-py3.
It is a universal, pure-Python package.  The documentation reflects
the new name and repository URI.  The package metadata in setup.py now
includes maintainer information in addition to the existing author
information.

update docs and package metadata to prepare for fork