Add release notes for Review Board 2.0.17.

Review Request #7426 — Created June 15, 2015 and submitted — Latest diff uploaded

Information

Review Board
release-2.0.x
4c7315c...

Reviewers

This covers fixes for the regressions hit in 2.0.16, and the new
JavaScript extension fixes for reviews.

It also adds a missing timestamp on the 2.0.16 release notes.

Built the docs.