Mo changes - show alert prompt to reload when entering foreground

@StorkHQ/owners - not sure how I feel about this implementation yet

Will show alert when the app enters the foreground and has downloaded a new deploy - closes #36 

Changed...
```objc
[[Stork sharedClient] prepareDeliveryWithOnDeliverBehavior:kStorkBehaviorReloadNewDeploy withOnEnterForeground:kStorkBehaviorCheckNewDeploy];
```
Set by...
```objc
[[Stork sharedClient] setPromptToInstallUpdatesOnEnterForeground:YES];
[[Stork sharedClient] setTimeBetweenDeployChecks:5.0f];
```

**NOTE:** This WILL change more in the future. Got a better idea to make a new Stork protocol for a Stork object controlled by some sort of UI (like the StorkLoaderViewController)
Is there any way to tell if the DOM is done loading? You might be able to inject some JS event listeners if you wanted (I could help ya with this)