Consistency and usability of download options

[mialondon]

As a researcher

I want 'download' to mean the same thing whether I'm on a single or double page view

So that I get consistent results without having to learn a mental model specific to the UV

Download options should be consistent across single, double page views
User should be able to: download entire item; download selection of pages; download current view (e.g. zoomed in view); download whole image.

[mialondon]

Prior work: UniversalViewer/universalviewer#411
UniversalViewer/universalviewer#463
UniversalViewer/universalviewer#338

Stanford UX proposals: https://docs.google.com/document/d/1YJGne0JK4t_5ygC7wHvZrngw2TjTKHt8-Iq__L4Xklo/edit#heading=h.z39vnqgl2h60