Merge pull request #293 from jeff1evesque/python_data_validator

#267: Define 'file_upload_validation()'
#294: html_form.js, message indicating acceptable file formats
#294: html_form.js, add <span class='bold'> wrapper
Merge pull request #295 from jeff1evesque/js_html_form

#294: Acceptable 'file upload' type message
#296: form_svm.css, define definition for '.bold'
#296: form_svm.css, define definition for '.italic'
Merge pull request #297 from jeff1evesque/css_form_svm

#296: Define style for 'Acceptable 'file upload' message
#292: README.md, minor indentation change
#292: README.md, document Python's 'magic' module
Merge pull request #298 from jeff1evesque/doc_linux_packages

#292: Documentation: Install Python's 'magic' module
#292: README.md, remove single quotes
Merge pull request #299 from jeff1evesque/doc_linux_packages

#292: README.md, remove single quotes
#282: load_dataset.php, define 'foreach' skeleton-loop
#282: load_dataset.php, define 'file_name', 'file_temp' in foreach
#282: load_dataset.php, remove 'local variables'
#282: load_dataset.php, add 'local variables'
#282: load_dataset.php, minor comment
#282: load_dataset.php, properly add file properties to associative array
#282: load_dataset.php, add 'json_creator' to 'arr_upload'
#282: load_dataset.php, JSON encode 'arr_upload' array