Add Jekyll and Proofer tests

.travis.yml

+language: ruby
+rvm:
+  - 2.1
+
+before_install:
+  - export NOKOGIRI_USE_SYSTEM_LIBRARIES=true
+
+script:
+  - bundle exec jekyll build --drafts
+  - bundle exec htmlproof ./_site
+
+notifications:
+  email: false

Gemfile

@@ -6,4 +6,8 @@ gem 'coderay'
 gem 'rake'
 gem 'thor'
 gem 'activesupport'
-gem 'stringex'
\ No newline at end of file
+gem 'stringex'
+
+group :test do
+  gem 'html-proofer'
+end

_config.yml

@@ -68,4 +68,4 @@ kramdown:
     coderay_css: class
 
 include: [".htaccess"]
-exclude: ["lib", "config.rb", "Gemfile", "Capfile", "README.md", "LICENSE", "Gemfile.lock", "config", "log", "Rakefile", "Rakefile.rb", "tmp", "less", "*.sublime-project", "*.sublime-workspace", "test", "spec", "Gruntfile.js", "package.json", "node_modules"]
+exclude: ["lib", "config.rb", "Gemfile", "Capfile", "README.md", "LICENSE", "Gemfile.lock", "config", "log", "Rakefile", "Rakefile.rb", "tmp", "less", "*.sublime-project", "*.sublime-workspace", "test", "spec", "Gruntfile.js", "package.json", "node_modules", "vendor"]