v2 release WIP

[lavoiesl]

• [ ] https://github.com/Shopify/goose/pull/167
• [ ] https://github.com/Shopify/goose/pull/168
• [ ] https://github.com/Shopify/goose/pull/169
• [ ] https://github.com/Shopify/goose/pull/170

In no particular order:

• [ ] Get rid of global state
  • [ ] Inject Statsd backend
• [ ] Get rid of the Logger type
  • [ ] replace Global Fields -> Global client with fields
• [ ] Convert ContextLog to a logrus hook
• [ ] Extend LoggableError with Fault
• [ ] HTTP errors
  • [ ] Have an internal error for debugging purposes, and an external error with a message or status code.
• [ ] compare errors and fault from go-npt and open something similar in goose
• [ ] stats tag for errors