Add ancestor methods to BST

[saurabh0719]

Hi @TuTomasz

Is this repo being actively maintained? I'd like to add some more methods for regular BSTs (common ancestors, ancestor family etc.) and maybe introduce height balancing trees

[TuTomasz]

Hi @saurabh0719

I recently didn't have much time to add new features. If you would like to rework BST and add that to the repo you are welcome to do so. Thanks :)