Add testcase from Steffen, featuring inheritance. Works.
added asyncOneWayCheckNoResponse to check that async messages don't send a server response
send 204 No Content when there is no body message
do not return any content when the replyMsg is null
fix unit test to ensure errors are not emitted for empty response messages
do not try to read for empty data
Add changelog entry for Matt's oneway fixes
Fix support for multiple message parts in RPC mode.