I'm want to add functionality to my vivoactive so that it performs certain actions when I hit checkpoints in my runs. I know that I can't edit the default Run app and that developing an activity is pretty much the only way to make this happen. However, I don't want to have to build an entire app from the ground up. Does the Connect IQ OS require you to re-code everything in your new activity or can you piggyback/inherit from what's already provided?