Add initial implementation of Log4j Camel component.

  - Still needs more unit tests, but there's several that can be stolen from camel-core.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1588052 13f79535-47bb-0310-9956-ffa450edef68
Fix JavaDoc headers.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1588053 13f79535-47bb-0310-9956-ffa450edef68