Fix gallery tracking

Chrome removed the prefix on transform, breaking the originalEvent property name check. Also, the analytics datalayer had been updated and broke the summaryTag tracking. Jshint ignore required because of underscored variable :/
Hmm... the way I see it is that `gallery.galleryTitle === $(".fixture-incoming-slide")`, so shouldn't these rather be something along the lines of the following?

```javascript
expect($(".fixture-incoming-slide").find(".caption").text()).toBe("foo");
```

i.e.: More explicitly defining what you expect the outcome to be considering you know what's in the fixture.