Merge pull request mrackwitz#124 from kylebshr/master

Fix window crash on iOS 8

Author: mrackwitz

src/Blur/MRBlurView.m

@@ -151,7 +151,7 @@ - (UIImage *)snapshot {
     BOOL wasHidden = self.superview.hidden;
     self.superview.hidden = YES;
 
-    UIWindow *window = UIApplication.sharedApplication.delegate.window;
+    UIWindow *window = self.window;
 
     // Absolute origin of receiver
     CGPoint origin = self.bounds.origin;