updated pipeline-utilities to create data_intregity function. It takes an md5 of a file, and check  against a stored md5 if it exists, otherwise it just writes the md5 to a file next to the input file.
added workstation_data_check. This finds our engine deps, using the new_get_engine_dependency function, then finds all dirs in the engine_data_directory variable, and then runs data integrity on all nifti files found there .
Merge branch 'master' of github.com:jamesjcook/pipeline_utilities