[WIP] Unit testing and behavior tests

The CentralReport project is growing, it's time to implement tests!
Tests allow to ensure the integrity of the application is kept between versions and to ensure that all functionalities works well all the time.

CentralReport have two main parts:
- The bash part (installer/uninstaller)
- The Python part (the application)

We must create tests for:
- [ ] The bash functions
- [ ] The Python functions
- [ ] The global behavior: installation, starting/stopping CR, checking if the internal web server works well, etc.

- [ ] Must support many Python version (Travis will be useful for that)
- [ ] May support many OS (Vagrant can help)

Unless we found any surprise, we will use the "unittest" python module and the shunit library for the Bash part.