Popup: blue focus flash on android 4.2

So I tested this with Browserstack on android 4.2 and it fixed the problem.  However, when I run "grunt test" there are a number of test cases failing.  @arschmitz suggested I do a pull request so he can take a look.  So don't merge if it's breaking tests! :)
It's faster to use
```JS
if ( !$.contains( this._ui.container[ 0 ], this.document[ 0 ].activeElement ) ) {
```
[eight](http://jsbin.com/has-vs-contains) [times](http://jsbin.com/has-vs-contains-2/2/) faster, in fact.