[LOG4J2-682] Special characters (tab and so on) in PatternLayout do not work.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1605430 13f79535-47bb-0310-9956-ffa450edef68
Replace cascading if-else's with a switch on a char.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1605433 13f79535-47bb-0310-9956-ffa450edef68
Remove dead comment.

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/log4j2/trunk@1605436 13f79535-47bb-0310-9956-ffa450edef68