Merging in optimizations and simplifications of pullstudents.py

- Added in new classes for easier management: Student and Class (potentially renamed to Acad_Class)
- Deprecated old pull_repo() method for pullrepo() module with new pull_repo() method
- pullstudents.py and all new modules now use basic logging module logging, to be refined
- refactors pairs and students to be lists to be iterated through rather than dictionaries, key-pair nature for GithubID - Name encapsulated in the Student class.