Use HTML5 validation before sending off AJAX request.
Add minified script as well.
Update readme.md
Merge branch 'enhancement/use-html5-validation' of github.com:dannyvankooten/Easy-Digital-Downloads into dannyvankooten-enhancement/use-html5-validation
Merge branch 'dannyvankooten-enhancement/use-html5-validation'
Minify scripts and styles