Improve/safety

- Adds a new delegate:

```objc
- (void)dataSource:(ANDYFetchedResultsTableDataSource *)dataSource
     didMoveObject:(NSManagedObject *)object
     withIndexPath:(NSIndexPath *)indexPath newIndexPath:(NSIndexPath *)newIndexPath;
```

- Support hidden controllers:
```objc
@property (nonatomic) BOOL parentControllerIsHidden;
```

> If the controller is hidden it reloads contents without animations

- Refreshes cell contents when they get moved.
Otherwise we end up with crazy indentation from the beginning. We can have the same guideline for required parameters.

Like if you have:

`- (NSString *)uppercaseString:(NSString *)someString`

Then:
 `[[NSString alloc] initWithString:someString]` and `someString` is missing you can return `nil`

`if (!someString) return nil;`