Merge pull request #72 from Vydia/use-correct-method-queue

Fix iOS Hang by Using Proper Method Queue

ios/RNViewShot.m

 
 - (dispatch_queue_t)methodQueue
 {
-  return self.bridge.uiManager.methodQueue;
+  return RCTGetUIManagerQueue();
 }
 
 - (NSDictionary *)constantsToExport