Debugger: Remove dumper debugging output

Change-Id: I0dc23dd5d69885f8ddeb933ae644a983406bbb05
Reviewed-by: Jarek Kobus <jaroslaw.kobus@digia.com>
Prevent multiple inclusions of logging.h

Also provide destructor of QLoggingCategory inline.

Change-Id: Ic12cd0347eddcbfaddbd93ea8e9b9baa3307973f
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>