Add session02 folder and ack.py file
Add Ackermann function
Add testing for Ackermann function
Update ack function docstring
Add series.py file
Add Fibonacci function
Add Lucas function
Add sum_series function
Add test block for fiboncci, lucas, and sum_series functions
Change tabs to spaces in ack.py file
Merge pull request #39 from deFox22/session02

Session02 Task 1 and 2 Pull Request