chore(banner): Add news about material beta to the banner

Author: Naomi Black

public/_includes/_hero-home.jade

@@ -4,3 +4,10 @@ header(class="background-sky l-relative")
         img(class="hero-logo" src='/resources/images/logos/angular2/angular.svg')
         h1.text-headline #{title}<br>#{subtitle}
         a(href="/docs/ts/latest/quickstart.html" class="hero-cta md-raised button button-large button-plain" md-button) Get Started
+        
+    announcement-bar
+      .announcement-bar-slide.clearfix
+        img(src="/resources/images/logos/angular2/angular-banner-logo-grey.png" width="64")
+        p Test-drive <strong>@angular/material</strong>: 22 components now in beta.
+        a(href="https://material.angular.io/" target="_blank" class="button md-button") Try now
+