[add] Linking API

Adds support for opening external URLs in a new tab/window. Includes
patches to 'Text' to improve accessibility and 'createDOMElement' to
improve external link security.

Fix #198

examples/apis/Linking/LinkingExample.js

@@ -0,0 +1,29 @@
+import { Linking, StyleSheet, Text, View } from 'react-native'
+import React, { Component } from 'react';
+import { storiesOf, action } from '@kadira/storybook';
+
+class LinkingExample extends Component {
+  render() {
+    return (
+      <View>
+        <Text onPress={() => { Linking.openURL('https://mathiasbynens.github.io/rel-noopener/malicious.html'); }} style={styles.text}>
+          Linking.openURL (Expect: "The previous tab is safe and intact")
+        </Text>
+        <Text accessibilityRole='link' href='https://mathiasbynens.github.io/rel-noopener/malicious.html' style={styles.text} target='_blank'>
+          target="_blank" (Expect: "The previous tab is safe and intact")
+        </Text>
+      </View>
+    );
+  }
+}
+
+const styles = StyleSheet.create({
+  text: {
+    marginVertical: 10
+  }
+});
+
+storiesOf('api: Linking', module)
+  .add('Safe linking', () => (
+    <LinkingExample />
+  ));