chore(demos): fix quotation marks to pass lint

Author: kara

src/demo-app/demo-app.ts

@@ -19,7 +19,7 @@ import {ListDemo} from './list/list-demo';
 import {InputDemo} from './input/input-demo';
 import {LiveAnnouncerDemo} from './live-announcer/live-announcer-demo';
 import {GesturesDemo} from './gestures/gestures-demo';
-import {GridListDemo} from "./grid-list/grid-list-demo";
+import {GridListDemo} from './grid-list/grid-list-demo';
 
 @Component({
   selector: 'home',

src/demo-app/grid-list/grid-list-demo.ts

@@ -1,5 +1,5 @@
 import {Component} from 'angular2/core';
-import {MdGridList} from "../../components/grid-list/grid-list";
+import {MdGridList} from '../../components/grid-list/grid-list';
 
 @Component({
   selector: 'grid-list-demo',