mail attachment attach

Module should provide ability to add attachment directly in mail template/text to any email sent using drupal_mail().

For example If I want to add attachment to email that user receive after registration I should just open mail .tpl.php file and insert placeholder {attach_file filename=/docs/xxx.pdf name=xxx.pdf}.

Module will work that way:
Module implements hook_mail_alter after all other mail altering modules.
In this hook it parses message text for placeholders and removes them from text.