title: Grunt UseminPrepare Not Generating Configuration
body: <p>I am trying to use <code>grunt-usemin</code> to concatenate, minify, and remove unused optimized references from my project. I have set up the <code>build</code> blocks in my <code>index.html</code> file as so:</p>
  
  <p><strong>Index.html</strong></p>
  
  <pre><code>&lt;!-- build:js js/optimized.js--&gt;
  &lt;script src="app/app.js"&gt;&lt;/script&gt;
  &lt;script src="app/config.js"&gt;&lt;/script&gt;
  &lt;script src="app/config.exceptionHandler.js"&gt;&lt;/script&gt;
  &lt;script src="app/config.route.js"&gt;&lt;/script&gt;
  &lt;script src="app/common/common.js"&gt;&lt;/script&gt;
  &lt;script src="app/common/bootstrap/bootstrap.dialog.js"&gt;&lt;/script&gt;
  &lt;script src="app/controller1/controller1.js"&gt;&lt;/script&gt;
  &lt;script src="app/services/service.js"&gt;&lt;/script&gt;
  &lt;!-- endbuild --&gt;
  </code></pre>
  
  <p>and my <code>gruntfile.js</code> looks like:</p>
  
  <pre><code>"use strict";
  module.exports = function (grunt) {
  
  grunt.initConfig({
      pkg: grunt.file.readJSON('package.json'),
  
      useminPrepare: {
          html: 'index.html',
          options: {
              dest: '/dist'
          }
      },
  
      usemin: {
          options: {
              dirs: ['dist/index.html']
          }
      }
  });
  
  grunt.loadNpmTasks('grunt-contrib-concat');
  grunt.loadNpmTasks('grunt-contrib-uglify');
  grunt.loadNpmTasks('grunt-usemin');
  
  grunt.registerTask('testtask', ['useminPrepare', 'concat', 'uglify', 'usemin']);
  };
  </code></pre>
  
  <p>However, <code>usemin</code> never actually generates the <code>concat</code> or <code>uglify</code> methods in my <code>gruntfile.js</code>. Instead, when trying to run </p>
  
  <pre><code>grunt.registerTask('newtask', ['useminPrepare', 'concat', 'uglify', 'usemin']);
  </code></pre>
  
  <p>I get an error stating that "No "concat" targets found".</p>
  
  <p>My <code>gruntfile.js</code> and <code>index.html</code> are both in the root directory. Is there something I am doing wrong here?</p>
  
  <p><strong>EDIT: Running with <code>--verbose</code></strong></p>
  
  <pre><code>Running tasks: useminPrepare
  
  Running "useminPrepare" task
  
  Running "useminPrepare:html" (useminPrepare) task
  Verifying property useminPrepare.html exists in config...OK
  Files: [no src] -&gt; html
  Options: dest="/dist"
  Going through  to update the config
  Looking for build script HTML comment blocks
  
  Configuration is now:
  
    concat:
    undefined
  
    uglify:
    undefined
  
    cssmin:
    undefined
  </code></pre>