#636: data_validator.py, define 'mime_type' variable
#636: data_validator.py, change 'mime_type' -> 'mimetype'
#636: data_validator.py, append dict of 'mimetype: filedata' to 'json_keep'
#636: data_validator.py, correctly append dict of mimetype, filedata
Merge pull request #650 from jeff1evesque/python_data_validator

#636: Adjust 'file_upload_validation' return value