workaround aggressive minification not playing ball with IE8

I've had an issue when using [uglify](https://github.com/mishoo/UglifyJS2) to compress fine-uploader (as part of a bigger build job) in that it compresses 
```javascript
typeof something !== 'undefined'
```
to
```javascript
something!==void 0
```

which is all fine, but when it comes to the following chunk of code
```javascript
typeof(element.filters) !== 'undefined'
```
in IE8 we get problems. 

`typeof(element.filters)` in IE8 produces (or in my scenario produces) 'unknown', but when evaluating `element.filters` directly a 'Member not found' exception is thrown, killing the entire script.

Therefore I've put in a workaround that forces the typeof to remain in the minified code meaning everything works fine. Note this isn't a problem with the gradle minification. It leaves the typeof intact anyway.