When building for iOS 8, weak link to HealthKit. Once Xcode 6 is released, this will be changed to a regular weak_framework in the spec.
Add ability for HKMeasurement to vend HKQuantity's. Until Xcode 6 is released, takes pains to make sure that not only can it run on earlier versions of iOS but also can be built with earlier versions of the iOS SDK.
Update the example app to take advantage of the ASKMeasurement vending HKQuantity's where possible, and use an NSMassFormatter to display the weights.