Nodemailer.sendMail should be purely asynchronous.
Merge pull request #285 from jsdevel/forcing-async-in-sendMail

Nodemailer.sendMail should be purely asynchronous.
Fixes spelling mistake, SMPT -> SMTP
Merge pull request #288 from boboman13/master

Fixes spelling mistake, SMPT -> SMTP. Fixes #281
Upgrade aws-sdk to 2.0.5