Improve packaging

[4383]

• display readme.md content on pypi
• retrieve version from scm (git tag in our case)
• automatically deploy a new release on pypi when we push a git tag on github
• prefer cfg file to host project package config instead of python code

If you accept these changes then after you need to update the deploy section inside the .travis.yml file and you need to encrypt your password.

For further reading about how to deploy on pypi from travis you can read these docs:

• https://docs.travis-ci.com/user/encryption-keys/
• https://docs.travis-ci.com/user/deployment/pypi/

Also at each github push, CI will check readme syntax, packaging, etc, too

With these changes the next time you will push a new git tag on github it will build and deploy a related release on pypi automatically.

[coveralls]

Pull Request Test Coverage Report for Build 236

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at ?%

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Totals
Change from base Build 233:	0.0%
Covered Lines:
Relevant Lines:	0

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💛 - Coveralls

[4383]

I'm puzzled why we facing the py34 issue in CI... in my previous PR we don't have this issue and the code was identical, I'll spend some time to try to figure out why this error is raised.

[4383]

Well, I've switch from stestr to nose everywhere on unit test and CI seems happy now.

I suppose stestr possibly have some uncompatiblilities with python 3.4...

Anyway, I really prefer to use nose rather than stestr.