Fixed Android opened and received callbacks data types

package.json

@@ -1,5 +1,5 @@
 {
-  "version": "2.0.2",
+  "version": "2.0.4",
   "name": "onesignal-cordova-plugin",
   "cordova_name": "OneSignal Push Notifications",
   "description": "OneSignal is a high volume Push Notification service for mobile apps. In addition to basic notification delivery, OneSignal also provides tools to localize, target, schedule, and automate notifications that you send.",

plugin.xml

@@ -2,7 +2,7 @@
 <plugin xmlns="http://www.phonegap.com/ns/plugins/1.0"
     xmlns:android="http://schemas.android.com/apk/res/android"
     id="onesignal-cordova-plugin"
-    version="2.0.3">
+    version="2.0.4">
 
 
   <name>OneSignal Push Notifications</name>

src/android/com/plugin/gcm/OneSignalPush.java

@@ -85,14 +85,14 @@ private static void callbackSuccess(CallbackContext callbackContext, JSONObject
     if(jsonObject.has("payload")) {
       try {
         JSONObject payload = jsonObject.getJSONObject("payload");
-        if(payload.has("additionalData")) {
+        if (payload.has("additionalData")) {
           payload.put("additionalData", new JSONObject(payload.getString("additionalData")));
           jsonObject.put("payload", payload);
         }
       } catch (Throwable t) {t.printStackTrace();}
     }
 
-    PluginResult pluginResult = new PluginResult(PluginResult.Status.OK, jsonObject.toString());
+    PluginResult pluginResult = new PluginResult(PluginResult.Status.OK, jsonObject);
     pluginResult.setKeepCallback(true);
     callbackContext.sendPluginResult(pluginResult);
   }
@@ -102,7 +102,7 @@ private static void callbackError(CallbackContext callbackContext, JSONObject js
       jsonObject = new JSONObject();
     }
 
-    PluginResult pluginResult = new PluginResult(PluginResult.Status.ERROR, jsonObject.toString());
+    PluginResult pluginResult = new PluginResult(PluginResult.Status.ERROR, jsonObject);
     pluginResult.setKeepCallback(true);
     callbackContext.sendPluginResult(pluginResult);
   }