v3.1

Fixes issues in the enhancing of the metadata (for json files) for multi-echo data.
Upgrades dcmstack version to the master as of Dec 19, 2019.

Allowing grouping data from multiple sessions

I incorporated modifications from leej3/heudiconv, branch grouping_fix.

v2.9

Modifies convert.py to not extract _sbref phase images.

v2.8

• It adds the _phase contrast to func runs, to comply with BIDS 1.2
• It specifies the Debian version in the Dockerfile

v2.7

When a normalized/original pair of high-res anatomical images is present, only extract the normalized one as BIDS; the original is saved only as DICOM.
This way, if we run the images through MRIQC or fMRIPrep, we are not treating them as two different images.

v2.6

Fixed problem in convert.py for multi-echo _sbref files.

It fixes the name of multi-echo _sbref files.  Before, it added `_rec-magnitude` even when there wasn't a phase image.  Now it only adds it when needed.