Created impl subpackage and moved some classses to it. Implemented ExtendedThrowablePatternConverter and ThrowableProxy. Added Javadoc

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/branches/BRANCH_2_0_EXPERIMENTAL/rgoers@1172052 13f79535-47bb-0310-9956-ffa450edef68
33 files changed