participant2 features, dwi2mask, minor bugfix

Thanks @DimuthuHemachandra for new participant2 level features

New features:
-FA/MD-based connectivity matrices can now be produced with participant2 level analysis
-circleci testing for participant2 level analysis (with reduced dosenbach test atlas)
-dwi2mask for DWI brain masking instead of FSL (found to be more robust)

Bugfixes:

• DKE processing now re-enabled

Re-release for zenodo, to tag the version used in @DimuthuHemachandra manuscript submission