[CONFIGURATION-590] Removed implements Serializable clause.

Unnecessary serialVersionUID fields were removed, too.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1621618 13f79535-47bb-0310-9956-ffa450edef68
[CONFIGURATION-590] Updated changes.xml.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1621620 13f79535-47bb-0310-9956-ffa450edef68
Fixed checkstyle errors regarding the license header of package-info files.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1621621 13f79535-47bb-0310-9956-ffa450edef68