Add support for qCDebug and friends

Add support for qCDebug and categorized logging to Qt Creator.
For Qt 5.2 and newer we can just rely on the same feature in Qt.
For older Qt versions we declare a dummy class that has a hard-
coded configuration.

Change-Id: I4954616100c0a100675904ab25479ad84166227b
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>