qdoc: Adding the -log-progress option

qdoc: Adding the -log-progress option

qdoc now sends progress log messages to stderr
only if -log-progress appears on the command line.
The progress messages are not printed to stderr
if -log-progress is not used. i.e., -log-progress
is off by default.

Task number: QTBUG-27707

Change-Id: Id605d943506ab38639730bf16473b156d061dc53
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@digia.com>
Reviewed-by: Martin Smith <martin.smith@digia.com>