Responsive Changes

[new] Make AnsPress responsive
[new] Responsive captcha support
[new] Minified main CSS file (shaved 22KB)
[bug] Converted <button>s with .btn-primary class to input[type="submit"] which is what theme developers usually target their .btn-primary class on.
[bug] Fixed HTML semantics in content-list.php by reording the .wrap-right class.
[bug] Forced captcha to reload after form validation failed (even if the captcha was correct)