Added some investigation to nonempty errors
improved exception passing
Adding a second check
Improved check
New Freesurfer interface: MRIPretess
fix:added files to data folder so doctest passes
fix:docstring removed
Merge pull request #894 from oesteban/enh/FreeSurferMRIPretess

enh: Freesurfer mri_pretess
Merge pull request #890 from oesteban/bug/fixRemoveNonEmptyDir

Not empty folder in NFS errors