When MIME type of content rendered is "application/json" @context shall not be rendered

[jmcanterafonseca]

instead a JSON-LD Link header shall be provided as part of the HTTP response

[jmcanterafonseca]

the test on #18 shows that this issue remains

[kzangeli]

I added one more functest to cover the issue about context in payload/header depending on the Accept header.
What can I say, it seems to be working just fine.

I did get an error in "core context" and not "default context" though.
Curiously enough, this error only occurs when the context is in the payload, not when the context is in the http header (Link) ...

Will deal with this later (issue #18), not relevant for this issue.

See the functests:

• ngsild_context_in_header_or_payload_when_entity_has_no_context.test
• ngsild_context_in_header_or_payload_when_entity_has_a_context.test

visible starting from the branch task/65.one-more-functest-for-context-inhttp-header-vs-payload

[jmcanterafonseca]

still happening on ed9be30