On warm summer days, there's nothing better than a cold, refreshing pick-me-up. Starbucks is usually the first place we think of for such tasty beverages, especially lately. Over the past few weeks, particularly, the coffee chain has added plenty of new summer-appropriate drinks to its menu — and the best part is most of them have few calories — comparatively, of course. Sure, you can grab any of their Frappuccinos, but not only are those drinks high in calories, but they're also loaded with…