Deoldify Vapoursynth filter

[Dan64]

Hello Selur,

   I attached the wheel of the version 3.0 that I will release this weekend.
   Respect to the RC versions, I improved the descriptions of models and parameters (so please update the GUI).
   I also extended the list "ddtweak_p" with 2 additional parameters: gamma_alpha, gamma_min

   I discovered that a gamma value > 1.5 improves the ddcolor stability on bright scenes, while a gamma < 1 improves the ddcolor stability on dark scenes. 
   The decrease of the gamma with luma is activated using the new parameter gamma_alpha (if != 0).

    Here a comparison: https://imgsli.com/MjUyNjY0


Thanks,
Dan