Turns Response into a QObject and sets parent to the
command that emits it.
Each Command is also a child of the decorator commands,
Timeout and PageLoading commnds, so that deleting the
top level command will delete all the children.
See discussion in #430.
This prevents conversion of QByteArray to QString from truncating content at a null byte in the QByteArray. This truncation can be a problem if the response body is a binary object (e.g. PDF)
Fixes#322
Thomas Walpole