Added missing Enumerable#enum_for; it was previously just in Countable and Queryable.
Make Vocabulary::Term not Enumerable anymore.
Change Vocabulary#to_graph to Vocabulary#to_enum (and #enum_for), basically doing the same thing, but avoiding emergent problems.
Rename HTTP vocabulary to HT, to avoid unfortunate prefix, and to be consistent with general use.
Implement URI#pname to create a string form of URI#qname.
Implement Vocabulary.expand_pname.
Describe fuller vocabulary DSL.
Update vocabulary generation to serialize all properties (with no language or language "en")
Update all built-in vocabularies.