Fix some document error.

SDWebImage/SDWebImageDownloader.h

@@ -82,8 +82,8 @@ typedef void(^SDWebImageDownloaderCompletedBlock)(UIImage *image, NSData *data,
  *
  * @param url The URL to the image to download
  * @param options The options to be used for this download
- * @param progress A block called repeatedly while the image is downloading
+ * @param progressBlock A block called repeatedly while the image is downloading
- * @param completed A block called once the download is completed.
+ * @param completedBlock A block called once the download is completed.
  *                  If the download succeeded, the image parameter is set, in case of error,
  *                  error parameter is set with the error. The last parameter is always YES
  *                  if SDWebImageDownloaderProgressiveDownload isn't use. With the

SDWebImage/SDWebImageManager.h

@@ -131,7 +131,6 @@ typedef void(^SDWebImageCompletedWithFinishedBlock)(UIImage *image, NSError *err
  * Downloads the image at the given URL if not present in cache or return the cached version otherwise.
  *
  * @param url The URL to the image
- * @param delegate The delegate object used to send result back
  * @param options A mask to specify options to use for this request
  * @param progressBlock A block called while image is downloading
  * @param completedBlock A block called when operation has been completed.

SDWebImage/UIButton+WebCache.h

@@ -134,8 +134,10 @@
  *
  * @param url The url for the image.
  * @param state The state that uses the specified title. The values are described in UIControlState.
- * @param success A block to be executed when the image request succeed This block has no return value and takes the retrieved image as argument.
+ * @param completedBlock A block object to be executed after the request operation 
- * @param failure A block object to be executed when the image request failed. This block has no return value and takes the error object describing the network or parsing error that occurred (may be nil).
+ *   completed. This block has no return value and takes three argument: the requested
+ *   `UIImage` object, the `NSError` object describing error that occurred, and an 
+ *   `SDImageCacheType` enum describing the source of the image obtained from.
  */
 - (void)setBackgroundImageWithURL:(NSURL *)url forState:(UIControlState)state completed:(SDWebImageCompletedBlock)completedBlock;
 
@@ -147,8 +149,10 @@
  * @param url The url for the image.
  * @param state The state that uses the specified title. The values are described in UIControlState.
  * @param placeholder The image to be set initially, until the image request finishes.
- * @param success A block to be executed when the image request succeed This block has no return value and takes the retrieved image as argument.
+ * @param completedBlock A block object to be executed after the request operation
- * @param failure A block object to be executed when the image request failed. This block has no return value and takes the error object describing the network or parsing error that occurred (may be nil).
+ *   completed. This block has no return value and takes three argument: the requested
+ *   `UIImage` object, the `NSError` object describing error that occurred, and an
+ *   `SDImageCacheType` enum describing the source of the image obtained from.
  */
 - (void)setBackgroundImageWithURL:(NSURL *)url forState:(UIControlState)state placeholderImage:(UIImage *)placeholder completed:(SDWebImageCompletedBlock)completedBlock;
 
@@ -160,8 +164,10 @@
  * @param url The url for the image.
  * @param placeholder The image to be set initially, until the image request finishes.
  * @param options The options to use when downloading the image. @see SDWebImageOptions for the possible values.
- * @param success A block to be executed when the image request succeed This block has no return value and takes the retrieved image as argument.
+ * @param completedBlock A block object to be executed after the request operation
- * @param failure A block object to be executed when the image request failed. This block has no return value and takes the error object describing the network or parsing error that occurred (may be nil).
+ *   completed. This block has no return value and takes three argument: the requested
+ *   `UIImage` object, the `NSError` object describing error that occurred, and an
+ *   `SDImageCacheType` enum describing the source of the image obtained from.
  */
 - (void)setBackgroundImageWithURL:(NSURL *)url forState:(UIControlState)state placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options completed:(SDWebImageCompletedBlock)completedBlock;