Patch release: UX and doc improvements

This is a usability and metrics release. Invitations are a little easier to understand, and can send out emails. The tour has been updated to include more team information.

We added a 'welcome tour' for new accounts, to introduce the task list explicitly.

There is now a report on the mainframe page that shows how many members there are, how many circles have been created, and what circles have been active in the last 8 months.