Finish 1.1.4.

* Add support for :unique_bnodes to writer.
Updates for RSpec 3.0.
Re-enable some Rubinius pendings that now pass.
Remove List#valid?, as it's implemented in RDF.rb.
Version 1.1.2.
Release 1.1.2.

* Remove List#valid?, as it's implemented in RDF.rb.