Update Gemfile dependencies.

Author: gkellogg

Gemfile

@@ -14,7 +14,7 @@ group :development, :test do
   gem 'rdf-spec',       github: "ruby-rdf/rdf-spec",            branch: "develop"
   gem 'rdf-turtle',     github: "ruby-rdf/rdf-turtle",          branch: "develop"
   gem "rdf-xsd",        github: "ruby-rdf/rdf-xsd",             branch: "develop"
-  gem 'sxp',            github: "gkellogg/sxp-ruby"
+  gem 'sxp',            github: "gkellogg/sxp-ruby",            branch: "develop"
   gem "redcarpet",      platform: :ruby
   gem 'simplecov',      require: false, platform: :mri
   gem 'coveralls',      require: false, platform: :mri

Gemfile-pure

@@ -14,7 +14,7 @@ group :development, :test do
   gem 'rdf-spec',       github: "ruby-rdf/rdf-spec",            branch: "develop"
   gem 'rdf-turtle',     github: "ruby-rdf/rdf-turtle",          branch: "develop"
   gem "rdf-xsd",        github: "ruby-rdf/rdf-xsd",             branch: "develop"
-  gem 'sxp',            github: "gkellogg/sxp-ruby"
+  gem 'sxp',            github: "gkellogg/sxp-ruby",            branch: "develop"
   gem "redcarpet",      platform: :ruby
   gem 'simplecov',      require: false, platform: :mri
   gem 'coveralls',      require: false, platform: :mri