Release 3.2.4

Vocabulary representation

• When reading a vocabulary, don't skip non-english literals.
• When writing a vocabulary, use language-map form for language-tagged literals with any in english serialized as the first entry of the map,
• Remove more redundant string freezes.
• Fixes #432.

Documentation

• Document and parse datatype/language maps as part of Term attribute definitions.
• Update documentation links to use gh-pages, and add action to publish gh-pages from Yard docs.
• Improve Vocabulary DSL documentation.
• Add Yard tag to prevent parsing vocabularies if :noDoc is set.

Other

• Exclude '_' and '-' from PN_LOCAL escapes. Not all reserved characters need to be escaped in SPARQL/Turtle, but they must be unescaped when encountered.
• Improve #quoted? accessor for RDF::Statement, and set it when parsing embedded triples in NTriples/NQuads.
• Update expectation for RDF:URI with a hash argument, due to updates to rspec-mock.
• Update Countable, Enumerable, and Queryable to include their Enumerator classes inline, and remove a separate enumerator.rb to address #433.