Dedicated download button

[motching]

Hello there! Thanks for creating baguetteBox, we're happily using it!

I'd like to create a download button for the displayed images. I saw that idea about putting it into the caption, but we'd like something more idiomatic, like a download icon in the corner.

I could hook into the DOM and dynamically add what I need with appends but that's a little convoluted. So I'm thinking of forking the lib and adding the change.

Would you merge this into your upstream repo if I make a PR?

Thanks!