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)