DEFAULT_FROM_EMAIL and user email passed as context.
The default behaviour now is to always add the user email to the message
body. This is useful in cases where the SMTP server does not allow
setting the From: and Reply-To: headers.
The default behaviour can be customized by changing email.txt template.
Added form_name field.
The form_name is displayed in the subject of the sent email.
Allows telling apart emails from different contact forms on the same site.