Minimal updates for Jekyll 2.0
Reorder _config for sanity
Update Bourbon files (4.0.2)
Default to layout: post for posts

Just a little less boilerplate. This also removes a bit of trailing
whitespace because it shouldn't have been there.
Set default layout for docs
Use jekyll-redirect-from instead of our other redirect method
Autogenerate acknowledgements
Update README to use bundle exec *

Also, referenced rake release task
Merge pull request #2035 from zpao/jekyll-update

[Docs] Update Jekyll + more