added function to iterate through all files and folder in root,  and to delete or retrieve a list of those, added more callbacks
added function to iterate through all files and folder in root,  and to delete or retrieve a list of those, added more callbacks

enketo/enketo-legacy,HydroLogic/enketo,makinacorpus/enketo,HydroLogic/enketo,makinacorpus/enketo,enketo/enketo-legacy,makinacorpus/enketo,makinacorpus/enketo,enketo/enketo-legacy,HydroLogic/enketo,makinacorpus/enketo,makinacorpus/enketo,SEL-Columbia/enketo,SEL-Columbia/enketo