Fix: 'module' object is not subscriptable

We shouldn't use `__builtin__` as a dictionary
Update util.py

On CPython2 one should use `__builtin__` module, not a `__builtins__` dict.
Merge remote-tracking branch 'graphite-project/master'
Merge remote-tracking branch 'graphite/master'
Merge remote-tracking branch 'graphite/master'
Merge pull request #183 from AgFlow/master

Fix: 'module' object is not subscriptable