sync token_dictionary variable name w/ classifier

precommit formatting

update with 12L and 20L i4096 gc95M models, multitask and quantiz code

move dicts to init

patch datasets save_to_disk

refer to token dictionary in self

Update with gene classifier, custom token dict, and str validate options (#329)

add option for hyperparameter tuning to cc.validate

update examples for predict_eval and handle roc for 2 cell classes

Update readthedocs for classifier

Add classifier module and examples