feat(gen): add image file as example

Add an image file and use it in main view as an example. Also
demonstrates imagemin working

app/index.js

@@ -285,3 +285,8 @@ Generator.prototype.packageFiles = function () {
   this.template('../../templates/common/_package.json', 'package.json');
   this.template('../../templates/common/Gruntfile.js', 'Gruntfile.js');
 };
+
+Generator.prototype.imageFiles = function () {
+  this.sourceRoot(path.join(__dirname, 'templates'));
+  this.directory('images', 'app/images', true);
+}

templates/common/root/app/views/main.html

@@ -1,24 +1,31 @@
 <div class="header">
   <ul class="nav nav-pills pull-right">
-    <li class="active"><a href="#">Home</a></li>
-    <li><a href="#">About</a></li>
-    <li><a href="#">Contact</a></li>
+    <li class="active"><a ng-href="#">Home</a></li>
+    <li><a ng-href="#">About</a></li>
+    <li><a ng-href="#">Contact</a></li>
   </ul>
   <h3 class="text-muted"><%= appname %></h3>
 </div>
 
 <div class="jumbotron">
   <h1>'Allo, 'Allo!</h1>
-  <p class="lead">Always a pleasure scaffolding your apps.</p>
-  <p><a class="btn btn-lg btn-success" href="#">Splendid!</a></p>
+  <p class="lead">
+    <img src="images/yeoman.png" alt="I'm Yeoman"><br>
+    Always a pleasure scaffolding your apps.
+  </p>
+  <p><a class="btn btn-lg btn-success" ng-href="#">Splendid!</a></p>
 </div>
 
 <div class="row marketing">
   <h4>HTML5 Boilerplate</h4>
-  <p>HTML5 Boilerplate is a professional front-end template for building fast, robust, and adaptable web apps or sites.</p>
+  <p>
+    HTML5 Boilerplate is a professional front-end template for building fast, robust, and adaptable web apps or sites.
+  </p>
 
   <h4>Angular</h4>
-  <p>AngularJS is a toolset for building the framework most suited to your application development.</p>
+  <p>
+    AngularJS is a toolset for building the framework most suited to your application development.
+  </p>
 
   <h4>Karma</h4>
   <p>Spectacular Test Runner for JavaScript.</p>