Feature/2.4.0

hmm... I'm not exactly sure if you guys want this. But I'm sending it in anyway for discussion. Issue I see is that docslate is still on jekyll 1.0.0. So I took one of your newer doc sites on jekyll 2.4.0 and stripped it of most things to almost a blank state. This is that.

I then added a Docker continuous development toolchain to build/run this project as I don't want to bother with rbenv/rmv. Made a minor fix to Gemfile to include a needed dependency for it to run in Docker.