title: Angular 2 Cannot find name SimpleChanges
body: <p>When the code is compiled i get this error: Cannot find name SimpleChanges. I am new to Angular 2, could you possibly help me find where the error is?
  Here's my home.ts:</p>
  
  <pre><code>import { Component } from '@angular/core';
  
  import { NavController } from 'ionic-angular';
  import {Observable} from 'rxjs/Rx';
  
  @Component({
    selector: 'page-home',
    templateUrl: 'home.html'
  })
  export class HomePage {
    date: Date;
    constructor(public navCtrl: NavController) {
      this.date = new Date();
    }
  
  
    ticks = 0;
    ngOnChanges(changes: {[propertyName: string]: SimpleChanges}){
      if(changes['ticks']){
          if(this.ticks == 20)
              this.ticks = 0;
      }
    }
    ngOnInit(){
      let timer = Observable.timer(0,1000);
      timer.subscribe(t=&gt;this.ticks = t);
    };
  
  
  
  }
  </code></pre>