Use the raw formatter for coffeelint

Summary: Using --reporter=raw exposes raw JSON output rather than a limited XML output. This allows us to pull more context from the coffeelint output.

Test Plan: arc unit

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11320