Keep a history of release notes.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1620901 13f79535-47bb-0310-9956-ffa450edef68
[CSV-128] CSVFormat.EXCEL should ignore empty header names

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/csv/trunk@1620902 13f79535-47bb-0310-9956-ffa450edef68