Add support for multiple GA trackers

[mattstratton]

https://developers.google.com/analytics/devguides/collection/analyticsjs/creating-trackers#specifying_fields_at_creation_time

The idea here is that the main DOD tracker code will always be inserted, and events can add their own in the config file for the event, which would be added if it exists.

[mattstratton]

// Standard code. Replace X's and domain with your own
ga('create', 'UA-XXXXXXXX-X', 'domain.com');

// Replace Y's with your account number. "b" can be anything you want.
ga('create', 'UA-YYYYYYYY-Y', {'name':'b'});

// Standard code. No change necessary.
ga('send', 'pageview');

// "b" can again be anything you want, but it MUST match "b" above.
ga('b.send', 'pageview');

[mattstratton]

Also, this is the standard tracking code stuff:

<script>
  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
  })(window,document,'script','//www.google-analytics.com/analytics.js','ga');

  ga('create', 'UA-45939822-1', 'auto');
  ga('send', 'pageview');

</script>

[mattstratton]

I'm not sold this is actually working right now :)