Drop of the "libjpeg-turbo jpeg8 ABI" feature

[Kevin Kofler]

Vít Ondruch wrote:
> Shouldn't be the feature page just deleted? Or archived in some better
> category such as "deferred"? There is 256 (nice number ;) incomplete
> feature pages, some of them are probably abandoned as this one. Would be
> nice to do some cleanup there, to see what is actively worked on.

FeaturePageObsolete? Which could carry any feature that was intentionally 
withdrawn or that has been in FeaturePageIncomplete for too long.

        Kevin Kofler