Correctly import top-level util module

[philippjfr]

Fixes #1134

[jlstevens]

Glad this is fixed, but can you explain it to me?

[philippjfr]

Honestly, I can't. Apparently a module has to exported with an explicit import and since we have from __future__ import absolute_imports enabled and:

import .util

isn't valid syntax, this was the only thing left to try and it seems to work.

[jlstevens]

Whatever it was, glad it is fixed! Merging.