Standardized metrics class to compute data set balance

[bvanessen]

For a labeled data set, can we build a metrics package that calculates how many labels exist, and of which type, and then the system can compute raw accuracy and corrected accuracy.

A secondary question is if we can create a cross validation library that split a single data set into a good cross validation set. Right now we can perform this partitioning based on a random distribution. A more advanced approach would be to make sure that the held-out portion of the data set is a representative sample of the data set.

[bvanessen]

One example of this is in the imbalance python package