allow json files in _data dir
add tests for json data
document json support
dot json;
Merge pull request #2369 from jekyll/json-data
Update history to reflect merge of #2369 [ci skip]
Update CI to use Ruby 2.1.2
Merge pull request #2374 from albertogg/update-ruby
Update history to reflect merge of #2374 [ci skip]
Be consistent with the HTML entities.