New tests skeleton and examples using pytest

Instructions (from the project root):
1. pip install -r requirements-devel.txt
2. py.test
Merge pull request #37 from ikame/pytest

New tests skeleton and examples using pytest
Configure PYTHONPATH when running py.test
Some integration tests for auth api.
Merge pull request #38 from ikame/pytest

Integration tests
- Refactor historical
- Refactor notifications service to use the new historical service
- Refactor attachments
WIP: change owner field.
Adding markdown service
Adding emoji post procesor
WIP
WIP