cleaner implementation of ans classifier

classifiers/ans_graph_creator.py

classifiers/answer_classifier/ans_data_io_helper.py

classifiers/answer_classifier/eval_ans_classifier_simple.py

classifiers/answer_classifier/train_ans_classifier.py

classifiers/answer_classifier/train_ans_classifier_simple.py

classifiers/region_ranker/train_rel_classifier.py

classifiers/region_ranker/train_rel_classifier_simple.py

classifiers/rel_graph_creator.py

classifiers/tf_graph_creation_helper.py

classifiers/train_classifiers.py