Two childControllerContainerView's are initialized

The `-childControllerContainerView` initializes two instances of `_childControllerContainerView`, both are added to the MMDrawerController's view. The issue occurs because the first initialization requests `self.view.bounds`. At that time `self.view` is `nil` so the view gets loaded, and `viewDidLoad` gets called. The `viewDidLoad` method sets the `childControllerContainerView`'s background color which leads to a second initialization of `childControllerContainerView` because at that time the view is still nil:  ![bildschirmfoto 2013-10-28 um 15 39 52](https://f.cloud.github.com/assets/1156152/1420361/e17fca3a-3fde-11e3-9610-4777938ed41f.png)

This can be fixed by modifying the `-childControllerContainerView` method to look like this:
```objc
-(UIView*)childControllerContainerView{
    if (_childControllerContainerView == nil) {
        CGRect b = self.view.bounds;
        if(_childControllerContainerView == nil) {
            _childControllerContainerView = [[UIView alloc] initWithFrame:b];
            [_childControllerContainerView setBackgroundColor:[UIColor clearColor]];
            [_childControllerContainerView setAutoresizingMask:UIViewAutoresizingFlexibleHeight|UIViewAutoresizingFlexibleWidth];
            [self.view addSubview:_childControllerContainerView];
        }
    }
    return _childControllerContainerView;
}
```