Make this project the best FFmpeg's Rust binding crate

[Donough Liu]

There are several FFmpeg's Rust binding crate outside.

• https://github.com/meh/rust-ffmpeg-sys
• https://github.com/mewlips/rust-ffmpeg
• https://github.com/imager-io/ffmpeg-dev-rs
• https://github.com/zmwangx/rust-ffmpeg-sys
• https://github.com/VictorCPH/ffmpeg
• https://github.com/bacek/rust-ffmpeg4-sys (A fork of 1.)

Prove this project is better than them.

[Donough Liu]

Done