Remove unused imports

(cherry picked from commit ec3483ae26)

game/scripts/utility/common_functions.rpy

@@ -8,12 +8,9 @@ init python early:
     import fnmatch
     import posixpath
     import re
-    import string
     import functools
     import timeit as timeit_module
-    from bisect import bisect
     from operator import itemgetter
-    from operator import add as _add
     from collections import OrderedDict
 
     get_volume_preference = renpy.game.preferences.get_volume