title: Function instead of interface name when using Reflect
body: <p>I've a problem with using reflect in field decorators. I've created a decorator with below signature:</p>
  
  <pre><code>export function Inject() {
      return function (clazz, name) {
          .......
          let typeName: string = Reflect.getOwnMetadata("design:type", clazz, name).name;
          .........
      }
  }
  
  class MyClass{
      @Inject()
      private $q:ng.IQService
  }
  </code></pre>
  
  <p>And I use @Inject on fields. It works when field type is class but when field type is interface, it returns <code>Function</code> not the name of interface. How can I fix it?</p>