Adapt openseadragon to support IIIF manifests

[dannylamb]

In order to render multiple pages using the openseadragon viewer, it needs to be adapted to accept a IIIF manifest.

Depends on #1263

See this documentation from Openseadragon for examples. I think we'd just use the first 'inline' method, but that's pure speculation until we get into the thick of it.

[dannylamb]

Linking to #932

[whikloj]

Currently I think we are using more of the XMLHTTPRequest for IIIF info.json method, which would also open us up to using the multiple request method for paged content.

[dannylamb]

Resolved via Islandora/openseadragon@1a37e48