make spline bbox wider
Merge branch 'slice_motion_correction' into testing

* slice_motion_correction:
  make spline bbox wider
ugly fix for wrong fitting
Merge branch 'slice_motion_correction' into testing

* slice_motion_correction:
  ugly fix for wrong fitting
fix condition for enough sample to fit spline
Merge branch 'slice_motion_correction' into testing

* slice_motion_correction:
  fix condition for enough sample to fit spline