Give script/proof the ability to be force-run. [ci skip]
Allow use of script/cibuild outside Travis. [ci skip]
Add push, pop, shift, and unshift Liquid filters.

Fixes #2892.
Release Jekyll :gem: v2.4.0
Merge pull request #2895 from jekyll/array-filters
Update history to reflect merge of #2895 [ci skip]
Merge pull request #2896 from jekyll/release-2-4

Release Jekyll :gem: v2.4.0
Add #2895 to release post.

#2896.
Release :gem: 2.3.0
Release :gem: 2.4.0
Update site history.
Fix link to #2895.
Update Font Awesome to v4.2.0.
Remove the unused fontawesome-webfont.eot.
Fix `transition` property.

http://caniuse.com/#feat=css-transitions
Merge pull request #2898 from XhmikosR/font-awesome
Update history to reflect merge of #2898 [ci skip]
Merge pull request #2899 from XhmikosR/master
Update history to reflect merge of #2899 [ci skip]