Original file name in content-disposition HTTP header

[HT-7]

I suggest adding a content-disposition header that contains the original file name.

The content-disposition HTTP header does not work just for downloads, but also for inline files that are previewed in the browser. For example, YouTube channel banners have content-disposition: inline; filename="channels4_banner.jpg", so that file name shows in the title and as a pre-filled file name in the "Save as" window.

[nokonoko]

This could possibly leak information not meant to be shared, however adding a option to enable this would work.