Modified terminalbuilder gen/impl to kick off the call in a future as soon as fire() is invoked, and then to expose results from that future instead of kicking calls off only once pojo()/future()/oneway()/etc are invoked. Deprecated oneway() as it doesnt really mean anything anymore.

This change will now allow terminalbuilders to return error()/status()/RfcXXXHeaderState/whatever to describe error conditions, to be implemented later