README for react-native 0.31

[Olexiy665]

Please, update README.md for usage your excellent plugin with react-native 0.31.

[micsay]

RN@0.32

:react-native-system-notification:compileReleaseJavaWithJavac
E:\reactNative\Camera\node_modules\react-native-system-notification\android\src\main\java\io\neson\react\not
ification\FCMNotificationListenerService.java:9: error: package com.google.firebase.messaging doesn't exist
import com.google.firebase.messaging.FirebaseMessagingService;

[micsay]

For usage ,we can use command react-native link react-native-system-notification except for AndroidManifest.xml, if you meet the same question oferror: package com.google.firebase.messaging doesn't exist ,you could solve by edit build.gradle inreact-native-system-notification\android:
From

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.facebook.react:react-native:0.19.+'
    compile 'com.google.code.gson:gson:2.3.+'
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.android.support:support-annotations:+'
    compile 'com.google.android.gms:play-services-gcm:9.0.1'
    compile files('libs/js.jar')
}

To

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.facebook.react:react-native:0.19.+'
    compile 'com.google.code.gson:gson:2.3.+'
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.android.support:support-annotations:+'
    compile 'com.google.firebase:firebase-messaging:9.0.1'
    compile 'com.google.android.gms:play-services-gcm:9.0.1'
    compile files('libs/js.jar')
}

[krapspark]

so should someone create a PR that includes the firebase dependency?