fail & shutdown if callback server cannot start correctly. refs #120
fail & shutdown if callback server cannot start correctly. refs #120

bartdag/py4j-eclipse,jonahkichwacoders/py4j,scott1028/py4j,scott1028/py4j,fouzelddin/py4j,njwhite/py4j,fouzelddin/py4j,njwhite/py4j,scott1028/py4j,phact/py4j,jonahkichwacoders/py4j,njwhite/py4j,jonahkichwacoders/py4j,fouzelddin/py4j,phact/py4j,phact/py4j