two changes to Snakefile, bugfix and update
two changes to Snakefile, bugfix and update

 - bugfix: calc_simulated_cv_error needs to have no df_filter, since
   it had no filter during the initial training

 - for interpolate_to_fsaverage, call that folder sub-groupaverage
   instead of just groupaverage

billbrod/spatial-frequency-preferences,billbrod/spatial-frequency-preferences,billbrod/spatial-frequency-preferences