clang-format ./pkg

Here I just invoked this: scripts/clang-formatter.sh ./pkg

This one is fairly large, so I don't know. It's up to you. If you have some work in progress in ./pkg dir then we can wait with this. If not, then it's a good occasion.

In fact you could also do the same scripts/clang-formatter.sh ./pkg with your work in progress. After clang-format only your newly written lines of code will be different from the code formatted here.

I looked through the diff to make sure that YADE_CLASS_* macros aren't getting unformatted. It looks good.

Maybe you prefer that I split this into one MR per directory in pkg:

• common,
• dem,
• fem,
• lbm,
• openfoam,
• pfv

Or I could split large commit into 15 smaller commits (alphabetically, by files).