AFNetworking/AFNetworking — pull request #1517 by dsexton (2013-10-18 16:11:30+00:00)
Title: Allow nesting of batch operations when operation count is zero

In some of our projects we nest our batch operations, for example:
```objc
NSOperationQueue *uploadQueue = [[NSOperationQueue alloc] init];
NSArray *groupOneBatch = [AFURLConnectionOperation batchOfRequestOperations:groupOneOperations progressBlock:^(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations) {
// Do something with progress
} completionBlock:^(NSArray *operations) {
NSArray *groupTwoBatch = [AFURLConnectionOperation batchOfRequestOperations:groupTwoOperations progressBlock:^(NSUInteger numberOfFinishedOperations, NSUInteger totalNumberOfOperations) {
// Do something with progress
} completionBlock:^(NSArray *operations) {
// All uploads complete
}];
[uploadQueue addOperations:groupTwoBatch waitUntilFinished:YES];
}];
[uploadQueue addOperations:groupOneBatch waitUntilFinished:YES];
```

If `[groupOneOperations count] == 0` then we can move on to `groupTwoOperations`