Helper function to create a resampled dataset
Arguments
- data
 data.framecontaining time-series features- train_rows
 integerdenoting the number of cases in the train set- test_rows
 integerdenoting the number of cases in the test set- train_groups
 data.framecontaining proportions of each class in original train split- test_groups
 data.framecontaining proportions of each class in original test split- seed
 integerdenoting fixed value for R's pseudorandom number generator
