Fixed bug in the run docker container script

[hakonhagland]

For background see #208 (comment).

The git root will not always be 3 levels up from the filename. Added a more advanced method to find the git root. Also added a test case.

[blattms]

With this, can I call the scripts anywhere?
I had the impression that there even have been assumptions where the venv directory was created. Seemed like it had to be created below scripts/python

While I would have created it directly in the root directory.

[hakonhagland]

Seemed like it had to be created below scripts/python

@blattms Yes, I tried now with "pip install ./docker" from the root directory, and there seems to be some assumptions in the script about the current directory being "<root>/docker" when running the docker python scripts. I will check what is going on.

[hakonhagland]

@blattms I have updated the script such that the user can do "pip install ./docker" from the root directory of the git repository or from anywhere he likes (instead of first cwd to docker and then do "pip install ."). Can you retest?