Add scrollToEnd to ScrollView and ListView

Summary:
**Motivation**

A basic task of making a React Native ScrollView or ListView scroll to the bottom is currently very hard to accomplish:
- https://github.com/facebook/react-native/issues/8003
- https://github.com/facebook/react-native/issues/913
- http://stackoverflow.com/questions/29829375/how-to-scroll-to-bottom-in-react-native-listview

**NOTE:** If you're building something like a chat app where you want a ListView to keep scrolling to the bottom at all times, it's easiest to use the [react-native-invertible-scrollview](https://github.com/exponent/react-native-invertible-scroll-view) component rather calling `scrollToEnd` manually when layout changes. The invertible-scrollview uses a clever trick to invert the direction of the ScrollView.

This pull request adds a `scrollToEnd` method which scrolls to the bottom if the ScrollView is vertical, to the right if the ScrollView is horizontal.

The implementation is based on this SO answer:
http://stackoverflow.com/questions/952412/uiscrollview-scrol
Closes https://github.com/facebook/react-native/pull/12088

Differential Revision: D4474974

Pulled By: mkonicek

fbshipit-source-id: 6ecf8b3435f47dd3a31e2fd5be6859062711c233

React/Base/RCTModuleMethod.m

@@ -480,10 +480,10 @@ SEL RCTParseMethodSignature(NSString *methodSignature, NSArray<RCTMethodArgument
         expectedCount -= 2;
       }
 
-      RCTLogError(@"%@.%@ was called with %zd arguments, but expects %zd. \
-                  If you haven\'t changed this method yourself, this usually means that \
-                  your versions of the native code and JavaScript code are out of sync. \
-                  Updating both should make this error go away.",
+      RCTLogError(@"%@.%@ was called with %zd arguments but expects %zd arguments. "
+                  @"If you haven\'t changed this method yourself, this usually means that "
+                  @"your versions of the native code and JavaScript code are out of sync. "
+                  @"Updating both should make this error go away.",
                   RCTBridgeModuleNameForClass(_moduleClass), _JSMethodName,
                   actualCount, expectedCount);
       return nil;