Update README.md

Added documentation for using Mandrill email service
Update secrets.js

Added mandrill configuration
Update generator.js

Added Mandrill option to generator
Update generator.js

Fixed issue where email provider was not being set correctly within the user controller.
The second instance of the `'var smtpTransport = nodemailer.createTransport(\'SMTP\', {'` was not being caught.
Update README.md

Added back instagram documentation
Merge branch 'master' of https://github.com/larsonjj/hackathon-starter into larsonjj-master
Updated mandrill demo login and keys
Added mandrill to features list, updated changelog