Add Wheel package support: Issue #228

[thombashi]

This PR adds a functionality to make packages for both tar.gz and whl (Wheel format).
For example:

$ python setup.py build
...
$ ls dist
markdown2-2.3.6-py2.py3-none-any.whl  markdown2-2.3.6.tar.gz

You will need to change to specify both packages when uploading packages to PyPI:

twine upload dist/markdown2-2.3.6-py2.py3-none-any.whl dist/markdown2-2.3.6.tar.gz

[nicholasserra]

Normally doing an sdist upload so i'll have to check into what's needed before I merge this. Thank you

[nicholasserra]

Finally diving into this. Gotta change how the release upload is happening. Question for ya:

I notice python setup.py build is now also generating some extra files:

/lib/markdown2.egg-info/dependency_links.txt
/lib/markdown2.egg-info/PKG-INFO
/lib/markdown2.egg-info/SOURCES.txt
/lib/markdown2.egg-info/top_level.txt

Should these be ignored? Not sure why they're popping up.

[thombashi]

You can ignore those files.
Files under *.egg_info/ are intermediate product generated by setuptools.
Adding *.egg_info/ to .gitignore might be useful.