$subject: subject of the mail
$text: text of the mail
+'EmailUserCC': before sending the copy of the email to the author
+$to: address of receiving user
+$from: address of sending user
+$subject: subject of the mail
+$text: text of the mail
+
'EmailUserComplete': after sending email from one user to another
$to: address of receiving user
$from: address of sending user
$subject: subject of the mail
$text: text of the mail
+'EmailUserForm': after building the email user form object
+$form: HTMLForm object
+
'EmailUserPermissionsErrors': to retrieve permissions errors for emailing a user.
$user: The user who is trying to email another user.
$editToken: The user's edit token.