Convert js/accountPrefsPage to ES6.

Review Request #8054 — Created March 11, 2016 and submitted — Latest diff uploaded

Information

Review Board
release-2.6.x
41bea50...

Reviewers

This converts the two views in js/accountPrefsPage to ES6. The transforms
herein are relatively simple--primarily just making use of syntactic sugar.
This also fixes up all the doc comments.

Ran js-tests.