Python 3 preparation: update tokenize use in cgitb.py. Note that the same interface that has changed incompatibly is also used in tools/pygettext.py. That file also needs fixing, but this patch does *not* attempt such a fix.

#!/usr/bin/env python
from __future__ import print_function
import zlib, base64, sys
print(base64.encodestring(zlib.compress(sys.stdin.read())))