New AutoColor adjustment filter

[Dan64]

On my tests the AviSynth script is encoded at about 40fps (using avs import in Vapoursynth), while the Vapoursynth version is about 2X faster.

Strange for me in a quick test, avs.ColorYUV2(autogain=true) was around 3000 fps and autoadjust.AutoGain around 450 fps.
Busy week this, week and I'm mainly afk 

I performed the tests on the completed FRED script (attached)

If effect using the "Benchmark" tool included in vsedit. I get a speed of 40fps for the AVS version and 450fps for the VS version.
So it seems that the bottleneck is AutoGain, but given the total result, for the moment I don't consider this an issue.
 
Dan