[MRG] - Refactor and organizational changes

[vc1492a]

This PR contains the following additions / changes:

• an MIT license is added
• a refactor is implemented
• adds a .gitignore file
• adds sample data for testing and examples
• adds a requirements.txt file
• adds a tests directory containing some initial unit tests
• adds a setup.py file for pip installs
• updates README.md

The following additions / changes will be committed in the future:

• adds a CHANGELOG.md file
• adds an examples directory
• adds a notebooks directory
• adds template files for continuous integration and coverage reporting

After merge, we ought to consider:

• deploying continuous integration and coverage reporting
• publishing to pypi for easier installs through pip
• uploading releases (which are tagged) to the repository

[vc1492a]

The following additions / changes have now been made:

• adds a CHANGELOG.md file
• adds an examples directory
• adds a notebooks directory
• adds template files for continuous integration and coverage reporting
• adds additional unit test resulting in full coverage

After merge, I believe good next steps would be the following:

• deploying continuous integration and coverage reporting
• publishing to pypi for easier installs through pip
• uploading tagged releases to the repository in conjunction with pushes to pypi
• open issues for the following improvements:
  • adding additional tests to ensure proper functionality and appropriateness of scores
  • adding dedicated documentation for users
  • improving the code examples with larger scale data
  • the ability to return a graph from top_authors
  • user warnings and error catching for incorrect input parameters