Build a countdown timer application

Well, here's another experiment just prior to flipping to WatchOS 2.  This application is a countdown timer that displays days/hours/minutes/seconds until a target time.

The application is mostly an exercise in date math, but it does highlight the limitations of the current OS -- that being that the application is pretty much just a remote display from the phone.  e.g. this application will not start, nor update if the paired phone is not connected.

Some other observations:

• Not quite sure how to ensure that the UI is updated with the exact countdown time prior to display.  These two behaviors seem a bit asynchronous.  The willActivate() method seems to be called a bit late, or the display update is latent.  I'm not going to worry too much until I flip over to WatchOS 2.
• I need to do some work with resource bundles, property pages, etc.  Basically to make this application look a bit more production ready. 
• Same thing with OS and hardware combinations.  I don't have a good feel how general these applications are; UI layout, properties, supported features, etc.  Some learning to do here.

Code is here.