footer: Update year (2013 -> 2014)
AdSense: change to responsive ad unit

Now use responsive ad unit by specifying exact size via CSS.
Delete A/B test JavaScript code.
About: add 2014 icon
CSS: About add clearfix to #about-logo-text
CSS: Delete unsed CSS files (about.css, techni.css)
Trivial web design improvement

* CSS: Delete unsed CSS files (about.css, techni.css)
* CSS: About add clearfix to #about-logo-text
* About: add 2014 icon
* AdSense: change to responsive ad unit
* footer: Update year (2013 -> 2014)
README.markdown: Fix typo