Add code formatting trigger

[TedLyngmo]

One way to minimize diffs when we cooperate is to agree on some formatting rules and put them into a tool, likeclang-format or similar. This could be enforced via a commit-trigger. I have my own clang-format files for different situations. I can format the whole code base with one of them in one commit and you can look at it at tell me what you think? If it's acceptable, we can add it to the repo.

[PanosPetras]

This sounds like a neat idea. You can add it to the repo. I checked #34 and I don't have any objections in the format of the code.