BF: missing manpage summary line
RF: Remove NIfTI-related functionality from hyperalign command

This duplicates functionality provided by 'dump'.
RF: Use standard option group
RF: Remove masking from hyperalignment; stop hard-coding compression

Masking is removed in order to replaced by something more functional,
i.e. iteration over unique values of an ROI/segmentation attribute.
Meandering around hyperalignment