Update docs regarding maven-compiler-plugin and annotation processing.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611975 13f79535-47bb-0310-9956-ffa450edef68
Add link to plugins.html from extending.html.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611976 13f79535-47bb-0310-9956-ffa450edef68
Add myself to doc authors.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611977 13f79535-47bb-0310-9956-ffa450edef68
Fix link and reference to "testing".

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1611982 13f79535-47bb-0310-9956-ffa450edef68