reduced logging levels for several log messages.  add logback config for testing
added logback as slf4j test implementation in protobuf and protobufmux modules.
added calculator RPC protobufs for testing.  implemented end-to-end tests around calculator RPC.  Moved to traditional logging by class with SLF4J.
added client and server tracing annotations to protobuf impl.  consolidated decoder classes into ProtobufCodec file.  added resource cleanup for old tests.  improved testing
test logging by default to file
added code to determine service names used for tracing.   added zipkin end-to-end tests.