iPhone library for starting/stopping app's services?

I've worked on several iPhone applications which all require some subset of the same services: RemoteIO audio, GPS, push notifications, face sensor activation, idle timeout disabling, etc, etc. The application delegate callback methods become bloated with all of this initialization code which is slightly different in each app.

So my question is: is there a library for handling all this? Some system that lets me say, "this app uses services A, B, 开发者_Go百科and C, and they should launch in this order"? The services would be defined so that they'll automatically get the application lifecycle callbacks they need, like the application going into the background, audio interruptions, etc.

This is pretty ill-defined, which is why I'm hesitant to write this code yet. If someone else has solved the problem then I can avoid duplicating all of the mistakes they made on their approach to a solution.

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The only one i could think of would be three20, but not sure if that isn't a bit too much. ( check http://api.three20.info/annotated.php)