Update should and fix tests
Update qs which fixes failing tests on Node 0.11.x

The behaviour of __proto__ has changed in recent versions of v8.
On Node 0.11.x, querystring.parse on qs@0.6.5 would return a null
prototype chain. qs@0.6.6 fixes this issue.
Update express
Merge pull request #334 from jamielinux/should

Update should and fix tests