Pull request to master

You can make this `for loop` more readable by making a `class` method in `EnemyViewController` to generate the array of enemies for you.
i.e.
```
self.enemies = [EnemyViewController generateEnemies:NUMBER_OF_ENEMIES delegate:self];
```

For adding the enemy views and indicators, and starting the life timer, `EnemyControllerDelegate` can have a new method like `- (void)enemyViewCreated:(EnemyViewController *)enemyView` then have the GameViewController implement this method:
```
- (void)enemyViewCreated:(EnemyViewController *)enemyView
{
   [self.view addSubview:enemyView.view];
   [self.view addSubview:enemyView.indicator];
   [enemy startLifeTimer];
}
```
Given this, I think we've also eliminated the need for the `self.indicators` property :)