Integrate LegacyTileSource when only static image

[azaroth42]

Requirements would be that the Image have an explicit height and width associated with the URL.

OSD Instantiation:

    var viewer = OpenSeadragon({
        id: "openseadragon1",
        tileSources: [
        {type: 'legacy-image-pyramid',
         levels: [{url:'http://www.shared-canvas.org/impl/demo1/res/image-f1r-c.jpg',
             height: 3411, width: 2405}]
        }
        ]
    });

And in the manifest:

{
  "@context":"http://www.shared-canvas.org/ns/context.json",
  "@id":"http://www.example.org/iiif/book1/annotation/p0001-image.json",
  "@type":"oa:Annotation",
  "motivation":"sc:painting",
  "resource": {
    "@id":"http://www.shared-canvas.org/impl/demo1/res/image-f1r-c.jpg",
    "@type":"dctypes:Image",
    "height":3411,
    "width":2405
  },
  "on":"http://www.example.org/iiif/book1/canvas/p1.json"
}

This probably requires #127 to be done first, however.