New SSL complete control radio button group

Resolves #186 
Hmm, don't think this is quite right. Shouldn't it be:

```php
if ( $this->get_setting( 'force-ssl', false ) ) {
	$ssl = 'https';
} else {
	$ssl = 'request';
}

Then you let the `use_ssl()` function do the work of figuring out if it should be http or https.