title: npm install using pre-release versions
body: <p>i want to use pre-release versions in my package.json to get some dependencies in the latest version (containing als pre-releases) but for some reasons it doesn't work in my case. The pre-releases are fully ignored. As an example lets use angular. If I ask <code>"angular": "&gt;=1.4.0-rc.0 &lt;1.4.1"</code> as an dependency, i would expect that i would get the version <code>1.4.0-rc.2</code> installed, but i get just the version <code>1.4.0</code>.</p>
  
  <p>The <code>npm info angular</code> shows, that there are some rc versions available like</p>
  
  <blockquote>
    <p>...<br/>
    '1.4.0-beta.4',<br/>
    '1.4.0-beta.5',<br/>
    '1.4.0-beta.6',<br/>
    '1.4.0-rc.0',<br/>
    '1.4.0-rc.1',<br/>
    '1.4.0-rc.2',<br/></p>
  </blockquote>
  
  <p>My package.json looks as follows right now</p>
  
  <pre><code>"dependencies": {
     "angular": "&gt;=1.4.0-rc.0 &lt;1.4.1"
  }
  </code></pre>
  
  <p>Any ideas why i dont get any rc versions? What do i have to do to get it working?</p>