Use strict mode for Javelin core
Summary: Enable strict mode for Javelin when running in NodeJS.
Test Plan: Made sure Aphlict still worked.
Reviewers: epriestley, Blessed Reviewers
Reviewed By: epriestley, Blessed Reviewers
Subscribers: Korvin, epriestley
Differential Revision: https://secure.phabricator.com/D11432