missing registration command

[maxpietsch]

I think adding the commands for the registration and composite warp creation would be good.

Rigid alignment to high-resolution structural (T2-weighted) space using normalised mutual information (NMI) based registration with FSL Flirt 8on the mean b=1000 s/mm2 shell. This transformation is combined with a non-linear registration9 of the T2w volume to the 40 weeks template10 to allow transformations between diffusion and atlas spaces. -- https://biomedia.github.io/dHCP-release-notes/dwi-shard.html