Using Mailgun with Craft Is it possible to use the Mailgun SDK with Craft at this point?

If not, is it OK to just the composer autoloader as a second autoloader (I'm about to test it, I'm just curious whether it's kosher or there's a different way of doing it that doesn't involve writing another plugin)?
The asker was able to solve their question and confirm that MailGun can be used with Craft. In the comment they state:


  Just FYI: requiring vendor/autoload.php (from my plugin) worked and
  correctly loads Mailgun. So I guess it works, it's just (more than a
  little) ugly


We have had success integrating Craft with MailGun in our plugins as well.  While we have not released our integration publicly, we have a Sprout Email MailGun integration used by our direct customers and we were able to successfully integrate with Email Lists and Campaigns, and allow users to build Emails using Craft templates with Live Preview and send them through the MailGun API.