Log Message:
Update ruby-actionmailer to 1.2.5.

Changes since 1.1.1:
* Backport of documentation enhancements. [Kevin Clark, Marcel Molina Jr]
* Correct spurious documentation example code which results in a
  SyntaxError. [Marcel Molina Jr.]
* Mailer template root applies to a class and its subclasses rather than
  acting globally. #5555 [somekool@gmail.com]
* Nil charset caused subject line to be improperly quoted in implicitly
  multipart messages #2662 [ehalvorsen+rails@runbox.com]
* Parse content-type apart before using it so that sub-parts of the header
  can be set correctly #2918 [Jamis Buck]
* Make custom headers work in subparts #4034 [elan@bluemandrill.com]
* Template paths with dot chars in them no longer mess up implicit template
  selection for multipart messages #3332 [Chad Fowler]
* Make sure anything with content-disposition of "attachment" is passed to
  the attachment presenter when parsing an email body [Jamis Buck]
* Make sure TMail#attachments includes anything with content-disposition of
  "attachment", regardless of content-type [Jamis Buck]
* Rename Version constant to VERSION. #2802 [Marcel Molina Jr.]
* Stricter matching for implicitly multipart filenames excludes files
  ending in unsupported extensions (such as foo.rhtml.bak) and without a
  two-part content type (such as foo.text.rhtml or
  foo.text.really.plain.rhtml). #2398 [Dave Burt <dave@burt.id.au>, Jeremy
  Kemper]
* Allow Mailers to have custom initialize methods that set default instance
  variables for all mail actions #2563 [mrj@bigpond.net.au]