LogLevel [was std.experimental.logger formal review round 3]

[Robert burner Schadek via Digitalmars-d]

As I have explained countless times, the configuration in source 
and through inheritance will always be more powerful and flexible 
than a config file. I'm not gone create any config file support, 
as there will be always one feature missing and there is just no 
way to anticipate all possible configuration requirements. So one 
shouldn't even try.