Release 2.2.4

• In Reader.open, attempt to locate a concrete reader before opening, and pass specific accept types for that reader. Otherwise, fallback to passing accept types for all readers.
• "TRUE", "tRuE", etc are not valid boolean values, but may be used to create boolean values. This is different than SPARQL. From RDF 1.1 Concepts: Lexical space: {“true”, “false”, “1”, “0”}
  From Turtle:

  true and false are case insensitive in SPARQL and case sensitive in Turtle. TrUe is not a valid boolean value in Turtle.

• Fix problem reporting on need for linkeddata gem.
• Tighten up double regexp.
  • Allows .1
  • Disallows +INF, and InF.
  • Disallows NAN
• Protect against mutating a frozen URI in Util::File.
• Do not use Array() to uses to_ary which has been deprecated (#351) (@abrisse)