Create a script to check any auto-update process regressions

We need to be strong against any update process regressions. The idea is to create a Python script that will:

1. generate an executable for a given version lesser than the current one, let's say 1.2.2 if the current version is 1.2.3;
2. start un local webserver containing all required files for a complete upgrade;
3. starts the executable using the local webserver as beta update canal;
4. start Drive and let the auto-upgrade working;
5. check that the Drive version is 1.2.3.

We will use Python to have a script working equally on all platforms. And indeed, that script must be launched before any new release.