title: Multiple versions of react (react-dom uses old react dependency)
body: <p>I was getting the famous <a href="https://gist.github.com/jimfb/4faa6cbfb1ef476bd105" rel="noreferrer">two versions loaded error</a>. I ran the line <code>npm ls | grep react</code>and got the following:</p>
  <pre><code>├─┬ react@15.1.0
  ├── react-addons-css-transition-group@15.0.2
  ├─┬ react-big-calendar@0.9.12
  │ ├─┬ react@15.1.0
  │ ├── react-dom@15.1.0
  │ ├── react-overlays@0.6.3
  │ ├── react-prop-types@0.2.2
  ├─┬ react-datetime@2.1.0
  │ └─┬ react-onclickoutside@4.9.0
  ├── react-dom@15.1.0
  │ ├─┬ react@0.14.8
  │ └── react-addons-update@0.14.8
  </code></pre>
  <p>It seems that react-dom uses <code>react@0.14.8</code> while the rest of my project uses <code>react@15.1.0</code>.</p>
  <p>What do I do to make react-dom not load this older version of react? I thought that this was the most up-to-date version of react-dom.</p>
  <p>Note: I am using npm version 2.15.1 and node version v4.4.4</p>