Initial commit of mail handler tester.
Initial commit of mostly working mailer.

Still much todo, including:
 * Make Ts and Cs button on application page disable/enable the Submit
   button.
 * Make user type selection show/hide PI fields and/or disallow is_funded
   choice fields.
 * Any other validation to do on Application form.
 * Make JS to fill in collated fields - work_required_collated,
   collaboration_collated