Merge pull request #302 from jeff1evesque/php_load_dataset

#282: Allow 'load_dataset.php' to upload multiple files
Merge pull request #305 from jeff1evesque/php_load_dataset

#282: load_dataset.php, comment 'var_dump(_FILES)'
#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
#303: data_validator.py, remove unnecessary line of code
Merge pull request #307 from jeff1evesque/python_data_validator

#303: data_validator.py, remove unnecessary line of code
#301: data_validator.py, use 'try-except' to ensure valid file
#301: data_validator.py, print message, and 'sys.exit()'
#301: data_validator.py, minor language change
#301: data_validator.py, minor language change
Merge pull request #308 from jeff1evesque/python_data_validator

#301: Ensure 'json_file_obj' exists
#301: data_validator.py, change 'try-except' langauge
Merge pull request #309 from jeff1evesque/python_data_validator

#301: data_validator.py, change 'try-except' langauge
#310: Submodule, add 'jquery validation'
Merge pull request #311 from jeff1evesque/submodule_jquery_validation

#310: Submodule, add 'jquery validation'
#300: data_validator.py, minor comment
#300: data_validator.py, minor comment