Add start frame and frames option to video comparison

[superyu1337]

Adds two new arguments:

• -s (--start) sets the frame to start the comparison process at. 0 is the first frame.
  • Renamed: --skip-frames sets the amount of frames to skip.
• --frames The amount of frames (in total) to compare.

Also adjusts the progress bar to only count the amount of frames that get computed.

Todo

• Fix compatibility with large --increment arg values
• Clippy errors

Closes #19

[FreezyLemon]

Maybe rename -s to --skip or --skip-frames? I think it's more intuitive and avoids the zero- vs one-based indexing thing.

[superyu1337]

Should --skip-frames be an Option<usize> internally or should I leave it at a usize with 0 as default?

[FreezyLemon]

Simple usize seems fine. skip_frames = 0 should be easy to understand

[superyu1337]

Well, it's ready to review then.
The changes heavily adjust the logic used to skip frames with --intermediate. I can't count btw, so someone gotta sanity check this. But from what I could tell it works fine.

[FreezyLemon]

I think there's a logic error hiding there w.r.t. end_frame. And forgive me for being strict, but I don't like calc_score becoming so complex if we can avoid it.

[FreezyLemon]

Tested it a bit and everything works fine. One nitpick though

[FreezyLemon]

Thank you!

[FreezyLemon]

@shssoichiro I forgot to squash this when merging. Not sure if it bothers you, if it does we can squash it manually on main

[shssoichiro]

No biggie. I'd rather keep it unsquashed than deal with rewriting history in main. Thanks!