Add catch to prevent data leakage when resampling data [feature/124/augmentation]

[tallamjr]

We need to ensure that when resampling to done via SMOTE, or other techniques, that there is not the risk of data leaking into the test set such that when one comes to evaluate the models it is not being tested on examples that also exist in the training set.

This can be done with a copying of the original data and perhaps checks to see if augmentation has already occurred elsewhere in the pipeline

[Catarina-Alves]

This issue is no longer relevant for the current version of snmachine. However, it must be taken into account during issue #246