title: custom cordova pushNotification wrapper returning observable
body: <p>the phonegap-plugin-push for cordova has several functions with the following syntax</p>
  
  <pre><code>function name(successCallback(),errorCallback(),options)
  </code></pre>
  
  <p>I want to write a wrapper function and return an Observable but I'm a little stuck on how to create it using typescript for angular2.</p>
  
  <p>so</p>
  
  <pre><code>name.subscribe((data)=&gt;{...},(err)=&gt;{})
  </code></pre>
  
  <p>So far I've mostly only subscribed to existing observable like http.</p>
  
  <p>so it should look like </p>
  
  <pre><code>public unregister(options):Observable&lt;any&gt;{
    if(window.PushNotification){
      window.PushNotification.ungregister(...)
    }
  }
  </code></pre>
  
  <p>Thanks for the help in advance!!</p>