Allow creation of moment+langs.js

moment+langs.js is a version of moment.js, prepackaged with all
languages.
Convert lang/hr.js to UMD

Somehow missed this file in #1012
Make jshint happy
Merge pull request #1057 from wyantb/moment+langs

Allow creation of moment+langs.js
Use github.com/moment instead of github.com/timrwood repo