title: vscode automatic type acquisition for jest
body: <p>I have vscode 1.9 and I want to have intellisense for jest tests. The problem is that <code>describe</code>, <code>it</code>, <code>expect</code> etc are globally available in jest and you don't need to <code>import</code> them in your test files. So vscode will not show intellisense for them. </p>
  
  <p>Is there any configuration for globals for automatic type acquisition? </p>