Use Macro F1 score with 5-fold CV instead of accuracy for all measurements

[NirantK]

• Use a randomized 5-fold CV, with a fixed seed state instead of a test split
• Measure F1, and Accuracy - just accuracy has no meaning
• Always print the confusion matrix via sklearn, or go all the way and seaborn it 🥇

Given above, would it be more useful to this within the notebook instead of a separate wonky CleanTwitter class?

[meghanabhange]

Yes, will get to this after resolving #4

[meghanabhange]

Resolved by #19