Merge pull request #969 from sunnylost/master

Translate shadowdom 301 into Simplified Chinese and update 201's trans mistakes.
Automatically updating the calendar
gh-936 chrome 33 digest updates.
- Update async call stack image.
- Optimise all images.
- Add intro sentence.
- Don't sound like a robot.
Automatically updating the calendar
Merge pull request #971 from umaar/digest-updates

gh-936 chrome 33 digest updates.
Merge branch 'master' of https://github.com/html5rocks/www.html5rocks.com
translate speed/layers