Starts implementing the delete_item method, that deletes the nth element from the list
Finished implementing a first version of delete_item
The special case node = 0  is needed
Finishes implementing delete
Adds search method in the implementation
Implements the get method, that returns an element at a given index
Implements first version of duplicates removal. Prepares everything for another version that would not store any extra information
Finishes implementing the remove_duplicates method that won't store any more info.
Implements a loop detection method