function generate_tokes at tokenize.py yields token OP (51) for colon,
while it should be token COLON (11). It probably affects other python
versions as well.

I'm attaching a minor sample that demonstrates this, running it returns
the following output:

1 'if' (1, 0) (1, 2) if a == 2:
1 'a' (1, 3) (1, 4) if a == 2:
51 '==' (1, 5) (1, 7) if a == 2:
2 '2' (1, 8) (1, 9) if a == 2:
51 ':' (1, 9) (1, 10) if a == 2:
1 'print' (2, 0) (2, 5) print 'hey'
3 "'hey'" (2, 6) (2, 11) print 'hey'
0 '' (3, 0) (3, 0)

I didn't check if there are problems with other tokens, I noticed this
with colon because I was trying to make some improvements on tabnanny.