the issue tracker. See also #15455 [ci skip]

This commit also addresses rails/docrails#169 and rails/rails#14159

Highlighted code

At 4a6eba32 mail sending example was rewrited from rails 2 format to
modern rails 3 approach. But passing parameter `recipient` to method
Notifier#welcome was lost.

Passing email as parameter makes this example more solid.

Added link in MIT license for Action Mailer README. I think this seems appropriate but commentary on this is not a bad idea.

Made the defaults section a little more readable and more to the point, giving a overview of the possibilities.

see: https://github.com/blog/738-sidejack-prevention-phase-2-ssl-everywhere