cv_generator: generate folds for nested cv
dfm_gen: added optional lowercasing parameter
estimator: estimate model and performance based on parameters
feat_select: select features based on textstat_keyness
metric_gen: convert output from estimator to model performance metrics
modelizer: updated for new pipeline
modelizer_old: old model pipeline
out_parser: now correctly exported
merger: Added custom clean option (sometimes not cleaning is preferred, even with lemmas)
merger, out_parser: Updated regex for filtering out non-words to also include email addresses (containing both @ and .)