Update Moment.js from 2.8.1 to 2.8.3

Project site
* http://momentjs.com
* https://github.com/moment/moment/

File source
* https://github.com/moment/moment/tree/2.8.3

Changelog
* https://github.com/moment/moment/blob/2.8.3/CHANGELOG.md

Difference between 2.8.1 and 2.8.3

1.8.3

Bugfixes:
* #1801 proper pluralization for Arabic
* #1833 improve spm integration
* #1871 fix zone bug caused by Firefox 24
* #1882 Use hh:mm in Czech
* #1883 Fix 2.8.0 regression in duration as conversions
* #1890 Faster travis builds
* #1892 Faster isBefore/After/Same
* #1848 Fix flaky month diffs
* #1895 Fix 2.8.0 regression in moment.utc with format array
* #1896 Support setting invalid instance locale (noop)
* #1897 Support moment([str]) in addition to moment([int])

1.8.2

Minor bugfixes:
* #1874 use  Object.prototype.hasOwnProperty  instead of obj.hasOwnProperty  (ie8 bug)
* #1873 add  duration#toString()
* #1859 better month/weekday names in norwegian
* #1812 meridiem parsing for greek
* #1804 spanish del -> de
* #1800 korean LT improvement

Change-Id: I60595e8ea41e136c7afee12ad3702ecec6dd4aef