Merge pull request #262 from jeff1evesque/php_load_dataset

#244: Send 'file upload' from ajax to PHP
#244: ajax_data.js, add array index to '.prop(files)'
#244: ajax_data.js, define 'FormData' object
#244: ajax_data.js, remove 'Array'
#244: ajax_data.js, add back 'Array'
#244: ajax_data.js, add 'file upload' to 'form_data', then add to 'arr_data'
#244: ajax_data.js, move 'local variable'
#244: ajax_data.js, 'console.log()' php return value
Merge pull request #263 from jeff1evesque/js_ajax_data

#244: JS - Send 'file upload' from ajax to PHP
#244: ajax_data.js, add 'contentType', and 'processData'
#244: ajax_data.js, add internal documentation on '@contentType'
#244: ajax_data.js, add internal documentation on '@processData'
#244: ajax_data.js, additional internal documentation on '@contentType'
#244: ajax_data.js, send 'arr_data', instead of 'form_data' array
#244: ajax_data.js, change key 'file' -> 'file_data_' + index, 'form_data.append()'
#244: ajax_data.js, properly assign 'file_data' for 'formData'
#244: ajax_data.js, properly assign 'form_data' to ajax 'data' property
#244: ajax_data.js, remove unnecessary 'arr_data'
#244: ajax_js, change 'console.log(arr_data)' -> 'console.log(form_data)'
Merge pull request #264 from jeff1evesque/js_ajax_data

#244: Send 'file upload' from ajax to PHP