* Adds, append, len, print operations for circular linked list
* Adds, prepend support
* Adds, delete from front of the list
* Adds, delete_rear support
* Adds, method documentations
* Adds, type checking and doctests
* Updates doctest for delete ops
* Addressing requested changes
* Removes unused import
* Fixes failing doctests
* Minor modifications...
* Improved Singly Linked List
Added String Representations of Nodes and Linked Lists
Added support for indexing and changing of Node data using indices.
* Added a few comments to Linked Lists
* Reformatted to conform to PEP8
* Added from_sequence.py
Convert a Python List to Linked List comprising of Nodes and return head.
* Added print_reverse.py
Recursive program to print the elements of a Linked List in reverse.
* Change 'is not None' for more Pythonicness
