trichar_w2v.py: compute_max_sim_score_for_group, max_sim_score to support compare and represent of positive, negative and target instances of suffix-driven words.
trichar_wordhood_train_ins_gen.py: in the instance generation for testing corpus (with gold label), affix-driven words that are in train_gold_trichar_prefix/suffix_word are also considered as "positive instance"