Calling completion callbacks in the main thread.

- made sure this is true even if the downloader is used on its own
- SDWebImageManager doesn't need to perform a dispatch to the main thread any longer

@@ -237,7 +237,13 @@
                 {
                     UIImage *image = [UIImage decodedImageWithImage:SDScaledImageForPath(self.request.URL.absoluteString, [UIImage imageWithCGImage:partialImageRef])];
                     CGImageRelease(partialImageRef);
-                    if (self.completedBlock) self.completedBlock(image, nil, nil, NO);
+                    dispatch_async(dispatch_get_main_queue(), ^
+                    {
+                        if (self.completedBlock)
+                        {
+                            self.completedBlock(image, nil, nil, NO);
+                        }
+                    });
                 }
             }
 

@@ -99,24 +99,21 @@
             if (options & SDWebImageProgressiveDownload) downloaderOptions |= SDWebImageDownloaderProgressiveDownload;
             __block id<SDWebImageOperation> subOperation = [self.imageDownloader downloadImageWithURL:url options:downloaderOptions progress:progressBlock completed:^(UIImage *downloadedImage, NSData *data, NSError *error, BOOL finished)
             {
-                dispatch_async(dispatch_get_main_queue(), ^
+                completedBlock(downloadedImage, error, SDImageCacheTypeNone, finished);
+
+                if (error)
+                {
+                    [self.failedURLs addObject:url];
+                }
+                else if (downloadedImage && finished)
+                {
+                    [self.imageCache storeImage:downloadedImage imageData:data forKey:key toDisk:YES];
+                }
+
+                if (finished)
                 {
-                    completedBlock(downloadedImage, error, SDImageCacheTypeNone, finished);
-
-                    if (error)
-                    {
-                        [self.failedURLs addObject:url];
-                    }
-                    else if (downloadedImage && finished)
-                    {
-                        [self.imageCache storeImage:downloadedImage imageData:data forKey:key toDisk:YES];
-                    }
-
-                    if (finished)
-                    {
-                        [self.runningOperations removeObject:operation];
-                    }
-                });
+                    [self.runningOperations removeObject:operation];
+                }
             }];
             operation.cancelBlock = ^{[subOperation cancel];};
         }