Implement URL conflict checking in `jekyll-doctor`.
Nuke comment.
Call ruby's 'abort' if the site is unhealthy
Use Doctor#healthy? and ensure _all_ items are checked before process quits.
Update normalize.css to v2.1.2 and minify
Merge pull request #1389 from mojombo/doctor-conflicting-permalinks

Implement URL conflict checking in `jekyll-doctor`.
Update history to reflect merge of #1389
Add "pluralize" and "reading_time" filters to docs
Fix a misleading typo
Add update_normalize_css task
Remove duplicate
Merge pull request #1441 from sleeper/master

Fix a misleading typo
Update history to reflect merge of #1441
Merge pull request #1439 from bdesham/pluralize-and-reading-time

Add "pluralize" and "reading_time" filters to docs
Update history to reflect merge of #1439
Add code tags
Merge pull request #1445 from penibelst/patch-1

Add code tags
Update history to reflect merge of #1445
Fix TypeError on Generation

After several page build fails, this seems to have fixed up the following error:

lib/jekyll/excerpt.rb:108:in `partition': type mismatch: NilClass given (TypeError)
Merge pull request #1430 from penibelst/site-speed

Update normalize.css to v2.1.2 and minify