Add GA to the add-on

[sorgoz]

how to: http://developer.chrome.com/extensions/tut_analytics.html

Most interesting stuff to measure:

• how many active add-on per day are running
• how many times Warning Screen is shown
• What button/links on the WS users click and how often
• how many times rating window is opened

UA-2412412-8

[samitolvanen]

This would require a mention in the privacy policy.

[sorgoz]

well, implemented (details in confl). The rest is to update privacy policy.