add prev-event coords + save dataframe in comet for Q4

[salelkafrawy]

Hello Team,

• Just added two features I missed in the original PR (prev_event_x_coord and prev_event_y_coord).
• You might need to run tidy_data.py, split_data.py and process_data.py again to add them (if you are planning to use those features later on)
• Saved the filtered frame of the required game (id=2017021065) to comet under this url
• Finished the blog for Q4 (separate PR in the blog repo is ready)

[TimkLee]

FYI, the changes seems fine to me.