Add autoprunning of empty rooms

[bluehallu]

No description provided.

[kdbanman]

The patch is only 6 lines, and the feature seems reasonable and simple. Why hasn't it been merged?

[panuhorsmalahti]

By the way, it seems that this.sids is not cleared properly when a socket.io connection leaves a room.

Adapter.prototype.del = function(id, room, fn)
    this.sids[id] = this.sids[id] || {};

[gpestana]

@kdbanman Maybe because the rooms should be persistent even when they are empty. Maybe the best way to implement this functionality is to add a flag to the room indicating either if it should be deleted when empty or not. Or for the sake of simplicity, leave that decision to the upper layers.

[yads]

@gpestana this is likely causing memory leak issues seen here

[nebkam]

@gpestana Room creation is implicit - if you try to join a room that doesn't exist, it's created for you. That said, I think it's counter intuitive for the room deletion to be explicit.
Besides that, documentation concerning rooms is a bit misleading:

Upon disconnection, sockets leave all the channels they were part of automatically, and no specially teardown is needed on your part

[rauchg]

We should have this. Please rebase it.

[rase-]

Thanks @hallucynogenyc! Rebased and merged your fix in #10. :)

[bluehallu]

No problem, was actually rebasing now you saved me the effort 👍