ios: add audio notification and fix audio routing.

see comments in updateAudioRoute()

Author: zxcpoiu

index.js

@@ -1,5 +1,6 @@
 'use strict';
 var _InCallManager = require('react-native').NativeModules.InCallManager;
+import { Platform } from 'react-native';
 
 class InCallManager {
     constructor() {
@@ -65,15 +66,27 @@ class InCallManager {
     }
 
     async checkRecordPermission() {
-        let result = await _InCallManager.checkRecordPermission();
-        this.recordPermission = result;
-        return result;
+        if (Platform.OS === 'android') {
+            console.log('react-native-incall-manager: android does not support checkRecordPermission() yet.');
+            this.recordPermission = 'unknow';
+            return 'unknow';
+        } else {
+            let result = await _InCallManager.checkRecordPermission();
+            this.recordPermission = result;
+            return result;
+        }
     }
 
     async requestRecordPermission() {
-        let result = await _InCallManager.requestRecordPermission();
-        this.recordPermission = result;
-        return result;
+        if (Platform.OS === 'android') {
+            console.log('react-native-incall-manager: android does not support requestRecordPermission() yet.');
+            this.recordPermission = 'unknow';
+            return 'unknow';
+        } else {
+            let result = await _InCallManager.requestRecordPermission();
+            this.recordPermission = result;
+            return result;
+        }
     }
 }