proper documentation

push front added

allow dead code

ready for circular linked list

readme update with status

doubly linked list done

2 delete methods added to doubly ll

some extra methods added with dead_code allowed

dead_code allowed tag added

doubly_ll push_back done

Merge branch 'master' of https://github.com/hitmanbuzz/dsa_with_rust

implementing doubly linked list

singly linked list done

added readme with todo

singly linked list done