Migrate to annotation processor.

  - Commented out old method of pre-processing annotations.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1585234 13f79535-47bb-0310-9956-ffa450edef68
Add note about YAML.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1585235 13f79535-47bb-0310-9956-ffa450edef68
Add documentation regarding annotation processor.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1585236 13f79535-47bb-0310-9956-ffa450edef68
Migrate Flume plugin to use annotation processor.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1585238 13f79535-47bb-0310-9956-ffa450edef68
Fix LOG4J2-591.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1585240 13f79535-47bb-0310-9956-ffa450edef68