Commented Unassigned: JS ContentType is out of date [119]

Is there a reason we aren't using `application/javascript` instead of `application/x-javascript` for the contenttype of scripttransformer? I believe x-javascript is out of date. Happy to submit a PR for this.
Comments: In [Bundle Transformer 1.9.89](https://bundletransformer.codeplex.com/releases/view/619056) fixed this error.