Merge pull request #3 from dwbutler/master

Safer temp directory deletion
Implement pending << for Writable.
Remove unused RDF::Query and RDF::Vocabulary shared specs.
Update because of RSpec share_as deprecation.
enumberable #subjects/#predicates/#objects/#contexts/#each_graph pending specs
Enable non-unique contexts spec.
Remove matches FIXMEs
Remove queryable fixmes.
Merge remote-tracking branch 'origin/master'

Conflicts:
	lib/rdf/spec/writer.rb
Merged changes.
Version 0.3.10
Release 0.3.10
Mark as pending specs relying on Enumerable#enum_statement for JRuby 1.7.
Added Enumerable#valid? test.
Test that Writable#<< allows invalid statements to be added.
Version 0.3.11