Resolve #44: Rename TraceeConstants of MDC keys to traceeSessionId and traceeRequestId
Resolve #46: Rename HTTP and JMS header to "TPIC" (TracEE propagated invocation context)
Merge pull request #51 from SvenBunge/TPIC

Resolve #46: Rename HTTP and JMS header to "TPIC"
Merge pull request #50 from SvenBunge/MdcTraceeConstants

Resolve #44: Rename TraceeConstants ...