[C++] serialize BaseReply as BaseClass when serializing Reply
[C++] serialize BaseReply as BaseClass when serializing Reply

Change-Id: Ifb273274ed4e17b8daa98f205d3bac688c884c2b

bmwcarit/joynr,clive-jevons/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr