update to ember 1.3.1

Change-Id: Ia8ef4f9351bab01edb3fe989e628cfcb9412e227
Reviewed-on: https://gerrit.instructure.com/28542
Reviewed-by: Aaron Shafovaloff <ashafovaloff@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Stanley Stuart <stanley@instructure.com>
Product-Review: Stanley Stuart <stanley@instructure.com>