title: Input autofocus attribute
body: <p>I have places in my code where I have this:</p>
  
  <pre><code>&lt;input data-ng-disabled="SOME_SCOPE_VARIABLE" /&gt;
  </code></pre>
  
  <p>I would like to be able to use it like this too:</p>
  
  <pre><code>&lt;input data-ng-autofocus="SOME_SCOPE_VARIABLE" /&gt;
  </code></pre>
  
  <p>Or even better, mimicking how ng-style is done:</p>
  
  <pre><code>&lt;input data-ng-attribute="{autofocus: SOME_SCOPE_VARIABLE}" /&gt;
  </code></pre>
  
  <p>Does this exist in the current version of AngularJS? I noticed in the code there's a BOOLEAN_ATTR which gets all the attr's that AngularJS supports. I don't want to modify that in fear of changing versions and forgetting to update.</p>