Don't throw an exception when Array has been monkeypatched

[euank]

The simple reproduction case is: Array.prototype.noop = function() {} require('./youtube-feeds').feeds.videos({q: 'test'}, console.log);

This is a really big problem because a lot of modules monkeypatch Array and these other modules will break this one. It makes it practically unusable in any large projects.

[fvdm]

Fixed, thanks a lot!