Implement new message api to support specific text only on a given handler.

Setup Needs ability to send and receive emails Forum inbound messaging setup (Follow instructions of MDL-48227 or bully Andrew) bonus Jabber setup bonus Mobile notification setup. Regression testing Run all behat + phpunit and make sure they pass. Send messages to multiple users and from multiple users and make sure it works as before. Try sending messages using multiple processors and make sure it works as expected - email, popup, jabber etc (Site administration / ►Plugins / ►Message outputs / ►Manage message outputs) Try the inbound setup, sending -replying to email-make sure it works as before. Manual testing for the issue Go to My profile settings / ►Messaging Check all boxes under Subscribed forum posts and save Make post to a forum where you are subscribed. Run cron. You should get an email and it should contain the text "If you reply to this via email, don\'t include a quoted copy of this post." at bottom. Check that you got the same message in Moodle and it does not contain the text "If you reply to this via email, don\'t include a quoted copy of this post." In your email client enable "text only mails" (enable html only mails if it was already in text only mode). Repeat the above tests and make sure it still works in a similar way.