Shiv for "sortedIndex"

Shiv for "min" and "max" breaks "sortedIndex" on arrays of strings:

``` javascrpit
_.sortedIndex(['a', 'd', 'f'], 'c')
```

Second argument is transformed to `propGetterFactory`:

``` javascript
args[1] = propGetterFactory(args[1]);
```

https://github.com/floydsoft/angular-underscore/blob/master/angular-underscore.js#L28
