Flake8ify #2231

Fixed all flake8 issues

Task ID : 2231
Review ID : 343001
Merge pull request #86 from Abhisar/feature/task-2231

Flake8ify #2231
Refactor README

* Add FAQ and merge information from README of trytond_nereid
* Rename README.md > rst
* Use the README.rst on setup.py