update ruby version to 2.1.1

Address issue #6
Update config to use kramdown for markdown

#3 upgrade to kramdown
#2 - Initial changes to leverage Sass.  Updated default template to refer to local resources (though I think we need a variable here for ghpages branches).  Created placeholder includes.
#8 - Change pygments to highlighter
Include only generic logo, to be replaced by agency-specific logo after fork.
#9 - Replace generic Agency references with variables from config.yml.
Update README with Jekyll launch tips
Update swagger console to use relative paths, and include header/footer.  Issue: Navigation links not working properly.
Make navigation links relative
Update README with Jekyll launch tips
Merge pull request #7 from shawnjohnson/gh-pages

Address a few issues to make customizing the template easier