fix(demo-app) move menu icon inside of a button (#434)

src/demo-app/demo-app.html

@@ -23,7 +23,9 @@
   <div>
 
     <md-toolbar color="primary">
-      <md-icon (click)="start.open()">menu</md-icon>
+      <button md-icon-button (click)="start.open()">
+        <md-icon class="md-24" >menu</md-icon>
+      </button>
       <div class="demo-toolbar">
         <h1>Angular Material 2 Demos</h1>
         <button md-button (click)="root.dir = (root.dir == 'rtl' ? 'ltr' : 'rtl')" title="Toggle between RTL and LTR">

src/demo-app/demo-app.scss

@@ -25,7 +25,6 @@
 
   md-toolbar {
     md-icon {
-      padding: 20px;
       cursor: pointer;
     }