title: nvm keeps "forgetting" node in new terminal session
body: <h2>Upon using a new terminal session in OS X, <code>nvm</code> forgets the node version and defaults to nothing:</h2>
  
  <p><code>$ nvm ls</code>:</p>
  
  <pre><code>         .nvm
       v0.11.12
       v0.11.13
  </code></pre>
  
  <p>I have to keep hitting <code>nvm use v.0.11.13</code> in every session:</p>
  
  <pre><code>         .nvm
       v0.11.12
  -&gt;   v0.11.13
  </code></pre>
  
  <p>I've tried both the <code>brew</code> install, as well as the official installation script.</p>
  
  <p>My <strong><code>.profile</code></strong> for the brew version:</p>
  
  <pre><code>#nvm
  export NVM_DIR=~/.nvm
  source $(brew --prefix nvm)/nvm.sh
  </code></pre>
  
  <p>And for the install.sh script:</p>
  
  <p><code>$ curl https://raw.githubusercontent.com/creationix/nvm/v0.10.0/install.sh | bash</code></p>
  
  <pre><code>#nvm
  export NVM_DIR="/Users/farhad/.nvm"
  [ -s "$NVM_DIR/nvm.sh" ] &amp;&amp; . "$NVM_DIR/nvm.sh"  # This loads nvm
  </code></pre>
  
  <h2>Any clue to what I'm doing wrong?</h2>