Bump Jekyll to v2.3.0

https://github.com/jekyll/jekyll/releases/tag/v2.3.0
https://github.com/jekyll/jekyll/compare/v2.2.0...v2.3.0

@benbalter, this should solve some support tickets.
Merge pull request #87 from parkr/jekyll230

Bump Jekyll to v2.3.0