Feature Request: Root Folder Flag

[sohang3112]

I would like to request a new feature for labelimg: a root folder flag. This flag would allow users to specify the root folder for their images, labels, and classes.txt file when running labelimg from the command line.

For example, running labelimg --root=/path/to/folder/ would mean that the images folder is located at /path/to/folder/images/, the labels save folder is located at /path/to/folder/labels/, and the classes.txt file is located at /path/to/folder/labels/classes.txt. If a classes.txt file already exists in the specified location, it should be used.

Visually, the file structure would look like:

/path/to/folder
|- images/     
    |- *.jpg, *.png, etc.
|- labels/
    |- classes.txt
    |- *.txt - YOLO annotation label files

This feature would make it easier to organize images and annotations.