title: angulartics trigger event without event attributes
body: <p>Is it possible to trigger GTM event without using <code>analytics-on="click" analytics-event="Download"</code>?</p>
  
  <p>So I would like to add these tags over GTM interface or something so it's automatically added in GTM and Google Analytics.</p>
  
  <p>I followed instructions here
  <a href="https://github.com/angulartics/angulartics-google-tag-manager" rel="nofollow noreferrer">https://github.com/angulartics/angulartics-google-tag-manager</a>
  <a href="http://angulartics.github.io/" rel="nofollow noreferrer">http://angulartics.github.io/</a></p>