Add more modules
Add more modules

 * various helper/util libs
 * client libs for Contentful, Gengo, Slack, Stripe, and Twilio API's
 * promise-based HTTP client

ajnsit/hook.io,joshgillies/hook.io,joshgillies/hook.io,ljharb/hook.io,ajnsit/hook.io,joshgillies/hook.io,joshgillies/hook.io,ljharb/hook.io,joshgillies/hook.io,ljharb/hook.io,ajnsit/hook.io,joshgillies/hook.io,joshgillies/hook.io