Iterative fibonacci with unittests from slash (#882)

* iterative and formula fibonacci methods

Added two ways to calculate the fibonacci sequence:  (1) iterative  (2) formula.  

I've also added a timer decorator so someone can see the difference in computation time between these two methods.  

Added two unittests using the slash framework.

* Update test_fibonacci.py

* remove inline comments per Contributing Guidelines

* Update sol5.py

* Create placeholder.py

* Update and rename maths/test_fibonacci.py to maths/tests/test_fibonacci.py

* Delete placeholder.py

* Create __init__.py

* Update test_fibonacci.py

* Rename Maths/lucasSeries.py to maths/lucasSeries.py

* Update and rename Project Euler/Problem 01/sol5.py to project_euler/problem_01/sol6.py