Merge pull request #48 from moztw/master

Update Thunderbird's system requirement page
Add Universal Analytics

add universal analytics code
Fix the A/B test code
Merge pull request #52 from moztw/master

Update the production site
Add GA to irclog and translate sites
Merge pull request #54 from moztw/master

Add GATC for translate and irclog sites.
Add cookies domain name setting per GA's request for A/B Test
Merge pull request #55 from moztw/master

Modify AB Test code
Firefox 20.0 release notes.
Firefox 20.0 release, news and download links.
Merge branch 'firefox-release'
Update Fx 20 notes, add one security fix note.
Merge branch 'master' into production
Add TB 17.0.5
Add TB 17.0.5
Fix URL typo
Add news, update link
Fix TB 17.0.5 release date
Merge branch 'master' into production

Conflicts:
	htdocs/thunderbird/releases/17.0.5/index.shtml
	htdocs/thunderbird/releases/index.shtml
first commit of /firefox/tw page

the first version of /firefox/tw
To-do:
1.style it with sandstone
2.take some screenshot of fx-tw-ver
3.make it more contents