title: Npm install ignores tilde (~) in version number
body: <p>I would like to install 1.8.x version a package, and be able to later automatically update this dependency inside the >=1.8.0 &lt;1.9.0 range.</p>
  
  <p>I tried to run this command:</p>
  
  <pre><code>npm install example-package@~1.8 --save
  </code></pre>
  
  <p>Unfortunately it adds this record to my <code>package.json</code>:</p>
  
  <pre><code>"example-package" : "^1.8.0"
  </code></pre>
  
  <p>But what I want is this:</p>
  
  <pre><code>"example-package" : "~1.8.0"
  </code></pre>
  
  <p>How is it possible to do it with <code>npm install</code>, without manually edit the <code>package.json</code> file?</p>