Greasy Fork镜像

Added back old updateLoop code, see code comment for explanation & how to switch between the two.

requestAnimationFrame now able to be slowed down, improved code by https://greasyforks.org/en/users/475505-tettedev

Integrated scrubber hide css to not rely on external css.

Fixed rare cases of progress & buffer bars jittering on long videos w/ chapters.

Added comments back.

Fixed wrong buffer progress when controls are hidden.

Fixed progress bar scaling.