Fixes DownloadManager for IE10 and above

Fixes #4688.

It turns out that it is best to use `navigator.msSaveBlob` for IE10 and above (and possibly older versions, see https://stackoverflow.com/questions/20844644/why-am-i-getting-this-error-in-ie and https://stackoverflow.com/questions/16376161/javascript-set-file-in-download). Because of the feature test, this will only affect IE.