Automatically enforce coding standards

We currently have a "manual" definition of svFSIplus coding standards. I think it would be helpful to automatize what is written here with the widely used C++ code formatter clang-format (see usage here).

It seems like what we have is pretty much the Google C++ Style Guide. If we really need to, we can define modifications in a custom format file.

Once defined (and all existing code is formatted to that), we can only allow commits that satisfy this format as we do in svZeroDPlus. This will save developers time because they can automatically format their code and avoid future discussions about formatting when merging new code.

@ktbolt, please let me know what modifications from the Google C++ style you would like, and I can set up the rest. Thanks!