Hooking into Rmail
------------------

   To hook Mailcrypt into Rmail, use the following lines:

     (add-hook 'rmail-mode-hook 'mc-install-read-mode)
     (add-hook 'rmail-summary-mode-hook 'mc-install-read-mode)

   Using Emacs version 20.3 or higher, you should use the following
lines instead:

     (add-hook 'rmail-show-message-hook 'mc-install-read-mode)
     (add-hook 'rmail-summary-mode-hook 'mc-install-read-mode)