Update cordova.LocalNotificatioin.js

fix issues:
* cancelNotification() cannot pass notificationId
* cancelAllNotifications() always throw an exception

Notice:
if you want to cancelNotification(), notificationId need to be string
so when you use addNotification, pass notificationId as string, not int.
Merge pull request #5 from pizwu/patch-1

@pizwu update to cordova.LocalNotification.js