Import the 'with' statement to prevent an issue on Python 2.5 in test.
Update underscore.js

This updates us to 1.4.4, which contains a bunch of new features and bugfixes.

Reviewed at http://reviews.reviewboard.org/r/4196/
Fix a breakage with saving repositories without hosting services.

The recent hosting service change broke saving repositories when
not using a hosting service. We're now more careful in what we check.
Release Review Board 1.7.8.1.