Add example qtlogging.conf file to QLoggingCategory documentation

Change-Id: I0ceeb8afa711cc7bc1378287b0d550871e5bfd9d
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>
Improve debugging output for QLoggingCategory

Make sure that the source the rules are loaded from is printed before
any syntax errors.

Change-Id: Id7ced1a346dd0d8501eab93ac00e1f432ca6b703
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>
Improve debug output of QImage, QPixmap and QIcon.

Task-number: QTBUG-38858
Change-Id: Ie45d595478f971c7ed973d911c65484d947d2a60
Reviewed-by: Alessandro Portale <alessandro.portale@digia.com>