premailer/actionmailer_inline_css — pull request #20 by lafave (2013-10-30 21:54:58+00:00)
Title: Refactor + proper MIME nesting

#### Description
* Properly nests different MIME header parts as described here: http://msdn.microsoft.com/library/office/aa563064.aspx
* Refactors `InlineCssHook` to be more OO.