commit more functions

[z-jiaming]

We add more convenient and help functions:

• Support for entering multiple paths on the command line, separated by spaces
• args.video_names: pass multiple file paths to indicate which videos to evaluate
• args.overwrite: If the results.csv file already exists in the prediction folder, it will be skipped. This is to prevent accidental overwriting. If you want to overwrite it, specify -o or --overwrite, or pass overwrite=True (if used as a package).