Add support for Commons Logging. Cause SLF4J and JCL adapters to share  base Logger Context

git-svn-id: https://svn.apache.org/repos/asf/logging/log4j/branches/BRANCH_2_0_EXPERIMENTAL/rgoers@1125875 13f79535-47bb-0310-9956-ffa450edef68
22 files changed
tree: ac014858fcf332e57b35a643f5e24e83ade3b9d5
  1. log4j12-api/
  2. log4j2-api/
  3. log4j2-core/
  4. log4j2-jcl/
  5. slf4j-impl/
  6. pom.xml