Add release notes for stable/icehouse 1.3.1 release

1.3.1 is a bugfix release from the stable/icehouse branch.

Change-Id: I1ec24b0aaccb67e4f3043d481cec13d82dec3c0d
Add release notes for 1.4.0.0a4

Change-Id: Id2a6ae2616db33025dcbfa4fb0b76e38cba6292f
Merge "Add release notes for stable/icehouse 1.3.1 release"
Merge "Add release notes for 1.4.0.0a4"