@afni_refacer_make_master list-of-datasets

* This script makes a new mask/shell dataset for use with
   @afni_refacer_run. You probably do not need to run this script.
* This script has no options. The command line should be
   a list of T1-weighted dataset names that have NOT been
   skull-stripped or defaced or refaced.
* The output is a dataset afni_refacer_shell.nii.gz that
   contains the average 'face', which will be applied in
   script @afni_refacer_run.
* Where I say 'face', I mean 'non-brain tissue', which includes
   some skull regions, thus altering the outer shape of the
   head to some extent (including the ears).
* A minimum of 9 input datasets is required; 20 is probably
   enough to produce a master for refacing purposes.
* This script depends on the existence of two datasets:
   MNI152_2009_template_SSW.nii.gz = MNI-space skull stripping template
   afni_refacer_MNIbmask10.nii.gz  = MNI-space dilated brain mask
* These datasets should be in the AFNI executable directory, and are
   supplied with the pre-compiled AFNI binaries.
* The first dataset is used (by @afni_refacer_make_onebigA12 and
   @afni_refacer_run) to align a dataset to MNI space
* The second dataset is used to mask off the brain region when making
   the output dataset afni_refacer_shell.nii.gz
* Modifying this script, and the other @afni_refacer_XXX scripts, to
   use a different template will require replacing the two datasets
   listed above appopriately.
* And possibly modifying the 3dcalc command 'extend it downwards',

Author - The Face of Imperial Zhark, Who is Terrible to Behold!