Proposed solution to issue #8

This is my proposed solution to issue #8 (In ios 7 if i try to push a ViewController from your code it doesn't pass the Navigationbar but in iOS 6 it does.).

I only add a completion block to ``` - (void)dismissAnimated:(BOOL)animated ```

We normally show the sidebar on our navigation controller:
```
RNFrostedSidebar *callout = [[RNFrostedSidebar alloc] initWithImages:images];
    callout.delegate = self;
    [callout show];
```

Then dismiss it using ``` - (void)dismissAnimated:(BOOL)animated completion:(void (^)(BOOL status))finish;```:
```
- (void)sidebar:(RNFrostedSidebar *)sidebar didTapItemAtIndex:(NSUInteger)index {
	[sidebar dismissAnimated:YES completion:^(BOOL status) {
		if (status) {
			[self.navigationController pushViewController:myNewVC animated:YES];
		}
	}];
}
```

The advantage compare to the previous proposed solution is that you doesn't need to hide the navigation bar while the sidebar is shown.