Allow for custom subject lines in submitted form content

[warkior]

No description provided.

[jrevillini]

I've added this to my local version of FormBuilder. I'd like to be allowed to commit a patch, but I'm not sure how to get that permission. Quickly:

1. Open formbuilder/php/formbuilder_processing.inc.php
2. Find: if(!$source_email) $source_email = get_option('admin_email');
3. Just before that, insert:

        foreach($field_values as $key=>$value)
        {
            $form['subject'] = str_replace("~" . $key . "~", $value, $form['subject']);
        }

Now you can inject field values into the subject line by putting fieldname where you want the value to show up. This is the same method used in the autoresponse text and autoresponse subject line.