File download name issue

Hi

When I'm downloading the file using a fileUrl where the file is served by a nginx server, I'm also providing a fileName to change while downloading the file. But the file downloaded still has the old file name instead of the one I'm providing.

```
fileUrl = http://sever.com/x.txt
fileName = y.txt
saveAs(fileUrl, fileName);

```
File downloaded has the name x.txt instead of y.txt.