Feature Request: add Spline36 to resizing algo

[Krepax]

I perform a lot of downsizing from 1920x1080 to 1280x720 and I'm not very satisfied of the results. Bicubic usually generates a too soft image forcing me to use some sharpen filter while lancosz3 generates some ringing around the sharpest edges.

Would it be possible to introduce a spline based algorithm ?

Maybe the feature is already present in some unofficial build (I stick to the latest official 2.6.; in this case can somebody point me to a windows build using it?