Merge last changes from local repo into NIRAL repo

[bpaniagua]

Please, Mahmoud,

Can you merge your last changes into this repo? We are about to fix the windows compilation issues.
https://github.com/MahmoudMostapha/GROUPS

Thanks,
Bea

[phcerdan]

We have diverged from the upstream repo: https://github.com/ilwoolyu/GROUPS.

I think there are no changes in MahmoudMostapha fork of ours.

We should rebase our fork on top of upstream. See #9

[jcfr]

@juanprietob Would be great to coordinate with @ilwoolyu so that efforts aare put toward one project. See NIRALUser/MeshLib#3 (comment) for possible approaches

[jcfr]

The change to be be backported are the following: https://github.com/ilwoolyu/GROUPS/compare/cfaf88489d5bb2277fd823cd410e18b1e8839075...master

optimized triangle query - updated MeshLib required
added: an option to specify fixed subjects
update: fixed subject variable name convention
update: property z-score normalization
update: no-write coeff for fixed subjects