add classification function for 4 quality measures used by IPC

[ernestguevarra]

@tomaszaba as discussed in your repository, I will add a function in this package that you can use for IPC-specific purposes.

[tomaszaba]

@ernestguevarra great!

[ernestguevarra]

@tomaszaba been thinking about this and I realised that it might be more appropriate to create an IPC-specific package that will cover the checks and the calculations that you are doing.

This is because funding for the nipnTK work (not the package itself as that work is all my work without remuneration) was through NiPN and copyright holder for the code is NiPN and Mark. So, I think to avoid issues and to avoid complaints, it would make more sense to keep the two things separate.