#303: data_validator.py, check first 'uploaded file'
#303: data_validator.py, correct 'uploaded file' message, to first file
#303: data_validator.py, add 'for' loop to check all uploaded files
#303: data_validator.py, change index '0' -> 'index'
Merge pull request #306 from jeff1evesque/python_data_validator

#303: 'file_upload_validation' to validate multiple files