LUCENE-5850: Add missing hashCode implementation to Version.java

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1618621 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5892: CharsRefBuilder implements Accountable.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1618625 13f79535-47bb-0310-9956-ffa450edef68
LUCENE-5892: Missed the covariant return type.


git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1618628 13f79535-47bb-0310-9956-ffa450edef68