GET /line?parameters

This endpoint could provide alternate returns for certain parameters:

- ?text=blob a simple blob of textContent
- ?image=full the URL of the default resolution of a full page (found on the Canvas)
- ?image=line an image fragment of this single annotation
- ?lookup=project (page, manifest, layer, metadata[], group) find the related document or Array of documents and return that instead, the version allowed without authentication
- ?view=json is the default, no querystring request and is redundant
- ?view=xml is a chance to get the document as an XML file
- ?view=html is a readonly viewer HTML Document presenting the annotation
- ?embed=true instructs methods that would have returned a URI to expand that and dereference the full document in its place

These parameters are all mutually exclusive except embed and passing multiple or a nonsense combo ("?view=html&embed=true") is an error.