title: stop closing the modal by clicking backdrop or outside the modal
body: <p>I have used one angular2 <a href="https://ng-bootstrap.github.io/#/components/modal" rel="noreferrer">ng-bootstrap</a> modal in our code. </p>
  
  <p>I want the modal will not close when I click outside the modal. Currently the modal is getting closed while clicking outside.</p>
  
  <p>In angular1 I used to do this by [keyboard]="false" [backdrop]="'static'". But this is time it is not working in angular2. </p>
  
  <p>Here is my <a href="https://plnkr.co/edit/RhXR0QZ2DiOJoK58MpjB" rel="noreferrer">plunker</a></p>
  
  <p>My Open method is as follows: </p>
  
  <pre><code>  open() {
      const modalRef = this.modalService.open(NgbdModalContent);
      modalRef.componentInstance.name = 'World';
    }
  </code></pre>