Add confirmation dialog for delete settings

Fixes #60
Fix issue #81

1. Check each parent domain to see if it's in userRed/userYellow in
deciding whether to automatically cookieblock a domain.

2. Don't add the "userset" attribute when auto-cookieblocking.
Merge pull request #80 from EFForg/fix/issue-60

Add confirmation dialog for delete settings
Merge pull request #82 from EFForg/fix/issue-81

Fix issue #81
Merge branch 'master' into fix/issue-64

Conflicts:
	lib/contentPolicy.js
Only show the cookie warning in truly weird situations
Make UI consistent with users' default cookie settings

If user is blocking all cookies or (some) 3rd party cookies by default,
the UI should show these trackers as yellow, not green, before the
heuristic has blocked them.