title: Grunt watch config option "reload: true" doesn't pick up changes
body: <p>My setup has a <code>Gruntfile.js</code> that loads tasks from individual files, one being <code>all_sass.js</code>. I want to have <code>grunt watch</code> running, make changes to <code>all_sass.js</code>, and see those changes in effect without having to stop/start <code>grunt watch</code> manually.</p>
  
  <p>As I have it now, the terminal tells me that grunt watch can "see" when I change <code>all_sass.js</code>:</p>
  
  <pre><code>OK
  &gt;&gt; File "grunt/tasks/all_sass.js" changed.
  </code></pre>
  
  <p>But it doesn't actually reload the task or restart grunt watch. It continues to run with the same behavior, on the same files it was initially watching.</p>
  
  <p><strong>Gruntfile.js:</strong></p>
  
  <pre><code>module.exports = function (grunt) {
      // load all grunt tasks
      require('load-grunt-tasks')(grunt);
  
      grunt.initConfig({
          watch: {
              configFiles: {
                  files: ['Gruntfile.js', 'grunt/tasks/*.js'],
                  options: {
                      reload: true
                  }
              }
          }
      });
  
      // Load all tasks from the grunt/tasks folder
      grunt.loadTasks('grunt/tasks');
  
      grunt.registerTask('default', ['allSass']);
  };
  </code></pre>
  
  <p><strong>grunt/tasks/all_sass.js:</strong></p>
  
  <pre><code>module.exports = function(grunt) {
      var scssPath = 'dest/scss';
      var cssPath = 'dest/css';
  
      // Config
      grunt.config.set('allSass', {
          scssPath: scssPath,
          cssPath: cssPath
      });
  
      // sass
      grunt.config.set('sass.allSass', {
          options: {
              outputStyle: 'compressed'
          },
          files: [{
              expand: true,
              cwd: '&lt;%= allSass.scssPath %&gt;',
              src: ['**/*.scss'],
              dest: '&lt;%= allSass.cssPath %&gt;',
              ext: '.css'
          }]
      });
  
      // watch
      grunt.config.set('watch.allSass', {
          files: ['&lt;%= allSass.scssPath %&gt;/**/*.scss'],
          tasks: ['allSass'],
          options: {
              spawn: false
          }
      });
  
      grunt.registerTask('allSass', 'Compile sass', [
          'sass:allSass'
      ]);
  };
  </code></pre>
  
  <p>Any ideas how I can get this working?</p>