`vagrant -v` works again [closes GH-147]

lib/vagrant/command/version.rb

@@ -0,0 +1,12 @@
+module Vagrant
+  module Command
+    class VersionCommand < Base
+      desc "Prints the Vagrant version information"
+      register "version", :alias => %w(-v --version)
+
+      def version
+        env.ui.info "Vagrant version #{Vagrant::VERSION}"
+      end
+    end
+  end
+end