Improve documentation for new contributors and modern environments

[divyanshu-iitian]

Hi,

I noticed that this repository was developed during GSoC 2018 and relies on older software versions (e.g., Python 2.7, legacy PyTorch).

I would like to improve the documentation by adding a short section that helps new contributors understand these constraints and potential modernization directions, without changing existing functionality.

Please let me know if this is acceptable before I open a pull request.

Thanks!