LabeImageDetectorFactory should be LabelImageDetectorFactory

[JonathanCSmith]

Typo in this detector factory - quick scan seems correct, but due to fonts, the 'L' is actually an 'I'. This threw me for a loop when trying to diagnose an import issue.

[tinevez]

I know of it, my shame. I am delaying fixing it because it will break other modules and many scripts. But anyway the next update will include a refactoring of the tracking part, and will be breaking changes. So I will fix it then.