Placed additional (still minimal) restrictions on delay parameter.
Created more values in initialization to save re-calculations (made possible by additional restrictions on delay parameter)
Refactored all SETAR-dataset building functionality into its own function, also improved speed.
Cleanup
Implemented hyper parameter grid search selection
Moved grid size and max iterations to parameters.
Added support for specified delay with unspecified thresholds.
General improvements and added unit tests for delay and threshold search.