Release 1.1.6.

* Add :simple_compact_iri option to only use simple terms when creating compact IRIs.
* Enable SSL mode, and don't verify, when retrieving files.
* Added Context#from_vocabulary and script/gen_context to generate a JSON-LD context given an RDFS/OWL/schema.org vocabulary.
* Make loading remote context error fail, even if validate is not set (#11).
* Added :frame option to writer to specify frame to be used instead of context.
* Added Context#reverse_term to find a term definition reversed from that requested.
* Make Context#mappings, #mapping, and #languages private (used only in tests).
* Make Context#alias and #coerce protected.
* Added Context#find_definition to find a term definition.
* Detect lists having nodes shared across different graphs, and add fromRdf test to check for this.
Change context spec due to lack of timezone support in Ruby Date class and recent change in RDF::Literal::Date for local time support.
Let API open input files, allowing documentLoader to be used.
Version 1.1.6.1.
Use toRdf instead of reader interface in jsonld executable, so that a context found by Link header will be applied.
Release 1.1.6.1.

* In jsonld executable, let API open input files, allowing documentLoader to be used.
* Use toRdf instead of reader interface in jsonld executable, so that a context found by Link header will be applied.