Add support for selectionColor on Android TextInput

Summary:
public
This adds support to set the highlight color on TextInput on Android.  See https://github.com/facebook/react-native/pull/5678 for the iOS implementation.

Note : We will merge these two properties with one name 'selectionColor' in a follow on diff, and may move it to a style.

Reviewed By: nicklockwood

Differential Revision: D2895253

fb-gh-sync-id: 6f2c08c812ff0028973185356a8af285f7dd7969

Examples/UIExplorer/TextInputExample.ios.js

@@ -543,12 +543,12 @@ exports.examples = [
         <View>
           <TextInput
             style={styles.default}
-            tintColor={"green"}
+            selectionColor={"green"}
             defaultValue="Highlight me"
           />
           <TextInput
             style={styles.default}
-            tintColor={"rgba(86, 76, 205, 1)"}
+            selectionColor={"rgba(86, 76, 205, 1)"}
             defaultValue="Highlight me"
           />
         </View>