I'm pretty unhappy with the current state, almost no other chat
application (including other Matrix clients) work like this. The biggest
annoyance is opening *other* spaces will send you to the Space Home -
which is almost never what you want! Even though our Space Home is
awesome :-)
Now when you switch spaces, the last room in that space is stored and
will be restored. This also allows us simplify some of the
"open the last room" code. I made sure that this works for the two
special spaces "Home" and "Friends" so everyone can take advantage of
this better UX.
Since this is constantly-changing-state and the worst that can happen is
the wrong room opening on launch, I didn't bother migrating the existing
setting. We'll have to kill it eventually anyway when we make it
account-specific!
Use the forget function to leave a room everywhere this is both for consistency and to reduce dependencies. This way no dependency on RoomManager is required to leave a room and since in all cases they have an object they can just call the function.
