Automatically deploy babel-bot from master

[Daniel15]

• Create IAM credentials with bare minimum amount of access
• Add credentials to Travis as AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables (ideally in the UI so there's no risk of leakage, but encrypted in travis.yml is OK too)
• Run ./scripts/deploy.js after building, on commits to master (NOT for PRs)

You might need to adjust deploy.js a bit, I made some assumptions when writing it (region is us-west-1, function name is BabelBot) that might not actually be true.

[Daniel15]

@danez I think you said you'd be working on this.

[danez]

I think you are confusing me with someone, I'm not sure what this is about :)

[Daniel15]

Hahaha oops, I must have typed @d and selected the wrong person in the dropdown. I meant @DrewML. Sorry @danez 😛