Masked and fixed AVX512 compilation warnings

The ones that could be "fixed", aka where vectorclass was actually not used, have been fixed. For the others, I've declared vectorclass as a system library.

Note that this should fix (and not mask) also all the warnings in Phys and Analysis repositories.

Also note that the majority of vectorclass usages (if not all ?) is coming from the code of the VectorFitter, even if this code is spread a bit everywhere. Dropping it would help a lot removing vectorclass.