[INTERNAL] inflate and deflate at the same layer

The payload of a data transfer object is now inflated
in the DataTransferManager.

Change-Id: I601f3c74fc8704b83a3c65cea821a115379c5ac2
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/962
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>