Test against jruby (1.9 mode) and rubiniux 2.x.
Just use kramdown, so redcarpet doesn't break the jruby build.
Merge branch 'master' into parser_refactor

* master:
  Just use kramdown, so redcarpet doesn't break the jruby build.
  Test against jruby (1.9 mode) and rubiniux 2.x.