Implement group_by Liquid filter & tests.
Add link to Jekyll homepage
Reject nil entries in Site#read_things
Refactor data/[] fetching of item property.
Merge pull request #1796 from mojombo/fix-fetching-things

Reject nil entries in Site#read_things
Update history to reflect merge of #1796
Updates for the 1.4.1 release

The 1.4.1 release is on the v1-stable branch
Merge pull request #1795 from Ivoz/patch-1

Add link to Jekyll homepage
Update history to reflect merge of #1795
Reformat to match the rest of the file
Merge pull request #1788 from mojombo/group-by-filter-2
Update history to reflect merge of #1788
Unminify css
Fix version
Fix repo
Merge pull request #1804 from penibelst/site-fix-postv141
Update history to reflect merge of #1804
Add comments and site.GH_ENV
Merge pull request #1803 from penibelst/site-unminify-css
Update history to reflect merge of #1803