title: detect change of nested property for component input
body: <p>In a simplified way I have an Angular2 Component and an input object like this:</p>
  
  <pre><code>class MyObject{
   Prop1:string;
   Prop2:Number;
  }  
  
  @Component() 
  export class MyComponent{
   @Input() myObject: MyObject;
   DoSomethingIfProp1Change(){
    console.log(myObject.Prop1);
   }
  }
  </code></pre>
  
  <p>How can I detect if Prop1 was changed from Hostcomponent and then execute the DoSomethingIfProp1Change method from inside MyComponent?</p>