Check for class-imbalance and it's impact

[tommylau-exe]

This PR contains code that was used to calculate how balanced the calorie labels (classes) are in the data set with our current thresholds. The results are as follows:

• Low-calorie: 25%
• Average-calorie: 63%
• High-calorie: 12%

[tommylau-exe]

For posterity, the current F1 Score for each category (as calculated by the recently pushed code) is roughly as follows:

• Low-calorie: 0.81
• Average-calorie: 0.90
• High-calorie: 0.65

Seems to correlate pretty well with representation in the data set.

[tommylau-exe]

In addition, the confusion matrix generated by the recently pushed code looks roughly like the following:

	Predicted Low-Calorie	Predicted Average-Calorie	Predicted High-Calorie
Actual Low-Calorie	10765	2437	52
Actual Average-Calorie	2065	32897	979
Actual High-Calorie	74	2100	2977