Remove deprecated plugin 'jekyll-projectlist'

My plugin 'jekyll-projectlist' has been replaced by the data file feature in Jekyll 2.0 and thus became obsolete.
Nix that newline. [ci skip]
Merge pull request #2742 from fhemberger/patch-1
Update history to reflect merge of #2742 [ci skip]
Remove tag plugins that are built in to Jekyll
Autoload csv files from data directory
link issue number
map with proc for CSV loading
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]
hashrockets in CSV loading
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]
Fix minor typo on plugins docs page