Add code for token frequency distribution

stylometry_code.py

throne_of_glass/data/canon_works/assasins_blade_prequel.txt

throne_of_glass/data/canon_works/crown_of_midnight_2.txt

throne_of_glass/data/canon_works/empire_of_storms_5.txt

throne_of_glass/data/canon_works/heir_of_fire_3.txt

throne_of_glass/data/canon_works/kingdom_of_ash_7.txt

throne_of_glass/data/canon_works/queen_of_shadows_4.txt

throne_of_glass/data/canon_works/throne_of_glass_1.txt

throne_of_glass/data/canon_works/tower_of_dawn_6.txt

throne_of_glass/freq_distribution/all_canon_token_len.png