Updated gems to latest versions where applicable.
Added AllegroGraph ruby gem to Gemfile.
Added vim temp files to .gitignore.
Created test file for AllegroGraph.
Added allegro:size task to Rakefile.
Fixed handling of nil node in graph.
Updated .gitignore to handle vim temp files.
Made minor fomatting change in my_prefixes.rb.
Merge branch 'z04' into dev
Changed config to be hierarchical.
Updated dependent files.
Updated SPARQL queries to work with Dydra and AllegroGraph.
Added RDF store classes.
Updated Rakefile to use them.
Added DydraStore subclass of RdfStore.
Added abstract method errors.
Refactored Rakefile to remove multiple stores.