Add setters for an int verbosity to QDebug. The streaming operators
can check on the setting and output more information accordingly.
[ChangeLog][QtCore][QDebug] How verbose a single debug output should be
can now be fine-tuned by setting a verbosity on the debug stream.
Change-Id: I77001fcf1ef090a580d1a137bb5a667fc1bf1e1b
Reviewed-by: Shawn Rutledge <shawn.rutledge@digia.com>