Merge pull request #16 from twers/8_add_Google_Analytics

8 add google analytics
add a page and css for promption when the ie version is under 8
chang the html and css for ie which version is lower than 8
reuse the comments style of lessonplan for attachment comments
add comments for scratch attachments
display name for anonymous user
create home page controller for about-us page which would be the new homepage. Qiu
wrong typing. Qiu
add integration test for about-us page. Qiu
change h2 to h1. Qiu
style about-us page. Qiu
use default initial-scale. Qiu
add responsive style. Qiu
Merge pull request #19 from twers/10_integrate_about_us_page

10 integrate about us page
Tiny refactor for the about page.
Move the tests from home to site controller.
Merge pull request #18 from twers/11_improve_the_style_of_attachment_comments

主要是comments的优化
#3 add login fail message
#2 Make the lessonplan cover save with a preview version
Change login integration test. Remove email display after login fail.