Introducing Bootstrap!

Take a look at getbootstrap.com to get a hang of the markup. Older markup should degrade gracefully.
Use Mailgun stripped-text for message content
Merge pull request #75 from pieterbeulque/bootstrap

Introducing Bootstrap!
Merge pull request #76 from austinylin/wip-166-stripped-text

WIP 166 - Use Mailgun stripped-text for message content