title: Using Vue components - setattr - invalid attribute name
body: <p>I am in the early stages of using Vue.js, and have come unstuck when attempting to use components. The non component version of this code worked fine.</p>
  
  <p>The following returns an error, which I am having trouble deciphering, but it looks like I am passing a comma somewhere where there should be an attribute of the object.</p>
  
  <p>Is it clear where the issue is arising here?</p>
  
  <p><strong>Error</strong></p>
  
  <blockquote>
    <p>Uncaught DOMException: Failed to execute 'setAttribute' on 'Element':
    ',' is not a valid attribute name.</p>
  </blockquote>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>&lt;div id="list_render"&gt;
      &lt;ol&gt;
          &lt;todo-item
              v-for="item in todo_list",
              v-bind:todo="item",
              v-bind:key="item.id"&gt;
          &lt;/todo-item&gt;
      &lt;/ol&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>JS</strong></p>
  
  <pre><code>Vue.component('todo-item', {
      props: ['todo'],
      template: '&lt;li&gt;{{ todo.text }}&lt;/li&gt;'
  })
  
  var todo = new Vue({
      el: '#list_render',
      data: {
          todo_list: [
              { id: 0, text: 'Learn Vue' },
              { id: 1, text: 'Plan project' }
          ]
      }
  })
  </code></pre>