Read FreeSurfer m3z file

read_fs_m3z(filename)

## Arguments

filename file location, usually located at mri/transforms/talairach.m3z

## Value

registration data

## Details

An m3z file is a gzip binary file containing a dense vector field that describes a 3D registration between two volumes/images. This implementation follows the Matlab implementation from the FreeSurfer. This function is released under the FreeSurfer license: https://surfer.nmr.mgh.harvard.edu/fswiki/FreeSurferSoftwareLicense.