Adding kramdown for JRuby support.

Author: tjdett

Gemfile

@@ -10,7 +10,8 @@ group :test do
   gem 'libxml-ruby', :platform => [:ruby, :mswin]
   gem 'rake'
   gem 'yard'
-  gem 'redcarpet' # For Markdown
+  gem 'redcarpet', :platform => :ruby # For fast, Github-like Markdown
+  gem 'kramdown', :platform => :jruby # For Markdown without a C compiler
   gem 'rcov', '~> 0.9', :platform => [:ruby_18, :jruby]
   gem 'simplecov', :platform => :ruby_19
   gem 'simplecov-rcov', :platform => :ruby_19