v1.6.0: 🔼 feat(model): update 🔼 (#170)

* update reqs.txt

* comment out pca 2, 3

* add version to metadata and ddof=0

* use default x_delta

* oversampling, preprocessing, no pca

* downgrade imblearn

* update test

* update append to concat

* use list as indexer instead of set

* debug

* fix create model

* don't use split fx

* remove print statement