update Google Analytics Core Reporting API to v3

For future reference, I used the script below to grab dimensions and metrics one at a time by feature from the [Dimensions & Metrics Reference](https://developers.google.com/analytics/devguides/reporting/core/dimsmets).

I'm sure the script could be improved to automate the whole thing, but I didn't think of that until I was almost done.

```
// Key
arr = [];
$('#sessionmetrics')
  .siblings('.ind')
  .children('div')
  .children('code')
  .parents('.ind')
  .prev('h3')
  .each( function(){
    arr.push($(this).text())
  })
alert( arr.reverse() )

// Web View Name
arr = [];
$('#sessionmetrics')
  .siblings('.ind')
  .children('div')
  .children('code')
  .each( function(){
    arr.push($(this).text())
  })
alert( arr )
```