Merge pull request #48 from jeff1evesque/js_html_form

#47: Add 'html_form.js'
#47: index.php, add 'id' attribute to 'svm_dataset_file' input
#47: html_form.js, only add 'input' attributes if they are not 'undefined'
Merge pull request #49 from jeff1evesque/form_add_fields

#47: Properly add file 'input' buttons
#53: index.php, add 'Remove' buttons
Merge pull request #54 from jeff1evesque/form_add_fields

#53: index.php, add 'Remove' buttons
#55: html_form.js, Properly append element after 'Remove' button