Bug 1050131 Write a script to auto-extract from mozilla-central the standalone content into the loop-client git repo

Yes, this sets up the initial last import revision for the repository. I decided that we should commit this as part of the updates, so that we can keep track of the latest revision we synced from - and there's at least a short-term option for easily moving and configuring, with also added facility for us checking things in case something goes wrong.