Breaking change in GenericResponse behavior should be configurable to old behavior.

10.7.0 introduced a breaking change in the contents of the com.apama.cumulocity.GenericResponse.body member. This fix introduces a mechanism to revert to the old behavior. This can be done by setting a property in the correlator on startup: analyticsBuilder.genericResponse.body=payload. This may be needed for compatibility with applications running in a Streaming Analytics application in Cumulocity IoT.