[INFO] Feature, add/update rife frame interpolation

[Brutoloco]

I have tried that of only multiplying by 2.5025. the video of 2,976.... It has to be a long video to be noticed. There is no crash. The audio gets progressively out of sync at the end of the video. However the video lasts the same. The audio has not been altered. 

Partial FPS multiplication for a 23,976... video to 60fps... works unexpectedly, changing irregularly the original place of the FPS, unknown cause.

BUT STILL NOT TESTED YOUR NEW DEV VERSION

Post edit, checking new version:

I don't know what's the reason of outsync frames, but I know a way to reproduce the problem without having to encoding. The problem is visible using vapoursynth preview

- Put any video at 23,976 fps and open preview, without changing any setting (keep synth auto refresh deactivated)
- Choose any part of the video using TIME, not frame, for example I choose minute 22:00.
- Now, enable rifev4 fps to 60fps or multiply 2,5025
- Enable Synth auto refresh, and put the same time --> 22:00 for example

Check that the frame at that time now, is many frames away from the first frame. There is a delay.

This does not happen if I combine "rifev4 x2.5", and "Filtering, speed change, scaling frame rate output: 60fps". --> sync ok

But If I combine rife v4 x2.5025(or60fps) and scaling frame rate output to 60. The sync out persist. --> sync not ok

If I combine rife v4 x2.51(more than 60fps) and scaling frame rate output to 60. -> sync ok