This fixes some bugs in our following logic, due to our attempts to
prevent infinite loops when two people follow each other.

* Propagate all of leader's views to a new follower, even if those views
were originally created by that follower.
* Propagate active view changes to followers, even if the active view is
following that follower.
* Avoid redundant active view updates on the client.

Release Notes:

- Fixed bugs where it was impossible to follow someone into a view that
they previously following you into.