Fix Closure compiler error on objPos' trailing comma

Forum post: http://foundation.zurb.com/forum/posts/13006

This trailing comma is causing compile errors when using Closure:

```
closure_compiler: ERROR - Parse error. Internet Explorer has a non-standard intepretation of trailing commas. Arrays will have the wrong length and objects will not parse at all.
```

This comma is not present in the 5.2.2 version of Foundation https://github.com/zurb/foundation/blob/master/js/foundation/foundation.tooltip.js 

Removing it allows Closure to successfully compile this file.