Refactor CouchDbObject into DefaultNoSqlObject.

  - Back when I was looking into the APIs for some other NoSQL drivers, I noticed that almost all of them use Map<String, Object> as their document type. Only MongoDB uses a more specific class. Therefore, I've renamed the CouchDbObject class due to its versatility in supporting more NoSQL drivers in the future.
  - Updated tests that referenced the old class.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1606953 13f79535-47bb-0310-9956-ffa450edef68
Fix strange compilation error noted in LOG4J2-694.

  - Although this field could theoretically be final, javac does not appear to think so!

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1606954 13f79535-47bb-0310-9956-ffa450edef68
Add changelog note for LOG4J2-694.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1606955 13f79535-47bb-0310-9956-ffa450edef68
Use parameterized logging methods.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1606957 13f79535-47bb-0310-9956-ffa450edef68
Extend EventListener for listener interfaces.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1606958 13f79535-47bb-0310-9956-ffa450edef68