Bump to Jekyll 2.4.0
Bump to Jekyll 2.4.0

Release: https://github.com/jekyll/jekyll/releases/tag/v2.4.0
Diff: https://github.com/jekyll/jekyll/compare/v2.3.0...v2.4.0 (all the important stuff is in lib/)
Co-sponsored by @gjtorikian and @kansaichris who put a LOT of work into this.

With love from SF.

n060dyz/pages-gem,Stargator/pages-gem,github/pages-gem,n060dyz/pages-gem,jlord/pages-gem,github/pages-gem,mstred/pages-gem,JustinPatenaude/pages-gem,Stargator/pages-gem,JustinPatenaude/pages-gem,jlord/pages-gem,mstred/pages-gem