Create CHANGELOG.md.

Change-Id: I24cad56a2e5ad5d6656993c22735649181fe71aa
Release 0.3.0.

Change-Id: I8bfa71b69b3eed926f9dd163e69381b9b7ae510f
Bump version after release.

Change-Id: Iadafe7263d94f52a4f04b6274522e04e8b88e075