Add a link to the Opera extension in the readme

Also clarify that we'll be supporting even more browsers.
possible domains from the Peevsky network
Add thevoice.bg to the Peevsky list
Fix a major bug in the URL matching regular expression

First, the slashes were not properly
escaped. Second, the pattern would match
any domain which ends in a blocked domain.
Release version 0.6.2 - important regexp pattern fix
Move the chrome extension files in their own folder
Extract the blocked domains list & checker in a separate file
The build script copies the blocked domains list from common/

The reason is that I have not found any other way
to share this code between multiple extensions,
because Chrome extensions can not contain symlinks
or load code outside of the main extension folder
in any other way.
Update the readme to reflect the new repo structure
The chrome/blocked_domains.js will not be under version control
Rename a variable for clarity

currentDomains → blockedDomains
Refactor the warning page code to keep the proper current URL

Fixes #7

The URL is passed as a query string to the warning
page. The page will show it to the user and will
also pass it back to the background thread when
the user requests to continue to that URL anyway.
Release version 0.6.3 - fixes multiple tabs issues
Merge changes from master
Update blocked domains
Release version 0.6.4 - add more domains to the blocked list

Motivation: https://github.com/open-media/dancewithme/pull/5
Initial firefox extension code
Fix page replacement content
Implement a nsIContentPolicy that redirects to warning.html