update simplecov gem to 0.9
Remove tag plugins that are built in to Jekyll
Merge pull request #2748 from rusikf/hack
Update history to reflect merge of #2748 [ci skip]
Merge pull request #2751 from pathawks/kill-redundant-plugins
Update history to reflect merge of #2751 [ci skip]
add markdown-writer package

add markdown-writer package for Atom editor
Fix typo in site documentation for collections.
Merge pull request #2763 from zhuochun/master
Update history to reflect merge of #2763 [ci skip]
Merge pull request #2764 from MinnSoe/doc-typo
Update history to reflect merge of #2764 [ci skip]