Email: set mailcomposer options

[ryanbuiltthat]

Mailcomposer defaults to an encoding of quoted-printable. This seems to be causing some issues with html emails rendered on the server. Can we add a hook into the mc instance options?

[glasser]

Thanks! I've pushed a change to expose the mailcomposer module and allow you to pass a MailComposer object to Email.send so that power users can use its API directly.