Anatomical processing planning

[mwaskom]

We're going to need to add wholly-new anatomical pre- and post-processing. This will include:

• T1w/T2w registration, averaging, and bias-field removal. This work is mostly done here: https://github.com/mwaskom/prisma_preproc/blob/master/prisma_anat.py
• Executing recon-all, with expert arguments for hires data, perhaps with the HCP approach to pial surface estimation
• Relevant post-recon-all processing, including making a less-inflated surface for visualization and a graymid surface for voxel<->vertex mapping