accept annotations for Create/Update in IIIF JSON-LD Context

[ndushay]

• [x] show can supply iiif context if desired
• [x] new/create accepts iiif context
• [ ] edit/update/patch/put accepts iiif context
• [x] replace context URI with inline context to avoid hammering w3c

See also #19 and #21

[ndushay]

http://lists.w3.org/Archives/Public/public-rdf-ruby/2013Aug/0001.html has something about switching contexts

[ndushay]

• [ ] RDF vocab for IIIF context
• [x] substitute local IIIF context for external lookup (override documentLoader for json-ld? do it like OA? or does that override need to be elsewhere in the stack (lower level)?

[ndushay]

Closing, as issues #13 and #81 exist for the parts not yet done.