Add support for download exported files from google docs

[laffer1]

I'd like the ability to download google spreadsheets as excel files. With the stock google sdk, I'm able to do this. While the getExportedLinks() method shows the list of links and the types as a map, it does not offer a method to download the file.

Would it be possible to add a new method that work like downloadFile but takes a second parameter of a type and would be able to look at the getExportedLinks() to fetch it with the appropriate access token?

I've tried to describe what I'm doing in this stack overflow post.