[TIMOB-4248] Issues with 'Ti.UI.iPhone.appBadge' ans push notifications as '+2'

Description

When I use '+2' in push notification (Apple), my app badge is correctly increased by 2 (for example, it it was at 0, it passes at 2). Then, I use

Ti.UI.iPhone.appBadge = 0;

or

Ti.UI.iPhone.appBadge = null;

and the badge correctly disappears. BUT, if I redo a '+2' push notification, the badge is now at 4!

How you can reproduce this issue:

There is a piece of code (which can be placed alone in app.js since it uses the function *Ti.Network.registerForPushNotifications*):

// Ask for APN registration
Ti.Network.registerForPushNotifications({
	types: [
		Ti.Network.NOTIFICATION_TYPE_ALERT,
		Ti.Network.NOTIFICATION_TYPE_BADGE,
		Ti.Network.NOTIFICATION_TYPE_SOUND
	],
	success: function(e) {
		// Send a request to urbanairship to register
	},
	error: function(e) {
		Ti.API.warn('Push notifications disabled: ' + JSON.stringify(e));
	},
	callback: function () {
		// Remove the badge on the main application icon
		Ti.UI.iPhone.appBadge = 0;
	}
});

Now, the different steps: . be sure that the current value of the app application icon badge is 0 . with this code, subscribe to APN on an iPhone. . close your app (or put in in background) . send a notification with '+2' as badge value and 'hi' has text. . on your iPhone, when you receive the badge, open the app by accepting the notification . check the badge icon of your app, it should be '0' (because the code passe its value to '0': Ti.UI.iPhone.appBadge = 0; ) . re-send the same notification . this time, don't accept the notification . check the badge icon of your app, it will get '4' as value in stead of '2'