Added Merge Sort in Python

[sambey04]

Description

Merge Sort in Python

For Example:

• Added a file(s) named 'Mergesort.py' that implements 'Merge Sort'.

• Changed the algorithm for performance/readablity/bugs.

• Added documentation to the algorithm

How Has This Been Tested?

Works with Python 2.7

Types of changes

What types of changes does your code introduce? Put an x in all the boxes that apply:

• [ ] Bug fix (change which fixes an issue with the algorithm)

• [x] New Algorithm (non-breaking change which adds functionality)

• [ ] Documentation

Checklist:

Go over all the following points, and put an x in all the boxes that apply.

If you're unsure about any of these, don't hesitate to ask. We're here to help!

• [x] My code follows the code style of this project.

• [ ] My change requires a change to the documentation.

• [ ] I have updated the documentation accordingly.

• [x] I have read the CONTRIBUTING document.