Summary: This class provides an adapter for [[https://github.com/less/less.js/ | lessc]].
Test Plan: Wrote and executed unit tests.
Reviewers: chad, #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: epriestley, Korvin
Differential Revision: https://secure.phabricator.com/D8992
