update to latest jschannel that includes origin in notifications
Allow logout to be called before .request or .watch.

A slightly simpler solution to #2529 which pushes the majority of the logic into communication_iframe/start.js
Update the comment on the .logout handler for clarity.
Merge pull request #2928 from mozilla/logout_before_ready

Allow logout to be called before .request or .watch.

It's like opening Russian boxes when searching for the original PR!

The comment is updated. Merging.

Thanks @lloyd and @yourcelf!