Use thumbnails cropped to square for tiles in slideshow view

[acozine]

When I view search results in Slideshow format, I would like to see the full image, cropped to square when necessary, in each tile.

[mark-dce]

I'm pretty sure the fix to this issue should close #107 as well.

[jcoyne]

The options I can do in css are stretch to width or height (choose one, letterboxed) or cropped to square at original resolution. If we must have "full image, cropped to square" then we're going to need an image server, or we'll have to pre-generate an additional derivative.

[mark-dce]

Tufts said padding was fine, so just display letterboxes for landscape images and pillarboxes for portrait images - i.e. stretch longest dimension to fit, stretch other dimension proportionally

[jcoyne]

@mark-dce The problem is we need a single rubric to apply to all the images independent of their rotation. We don't have any technical metadata that states the orientation.

[acozine]

We will hold this ticket open for now. Once we have Tufts images in the system, we will take screenshots of the two options for thumbnail display with an explanation of the benefits and downsides of each. The third option is to turn slideshows off. To make it performant, the system probably needs an image server rather than fetching the thumbnails from Fedora.

[mark-dce]

Obsoleted by #133