Some notes on the implementation.

1: in the paper unsubscriptions are removed only from the view. In this
implementation they are removed from subs too.

2: in the paper a new subscription (newSub) is added to subs only if it was
not already present in view. This constraint is not neded for view, since view
is a set, and is maybe not intended in the case of subs. This
implementation sticks to the paper though. Feedback is needed asap.

3: since I have the suspicion that "view" is not necessary, in the
implementation it is possible to switch it off, by simply not setting any
value (or setting a negative value) for l in the configuration.
When view is switched off, subs will play the role of view, ie it will define
the communication graph. The algorithms are the same otherwise.

4: Lacking a description in the paper, I invented the following unsubscription.
When a node wants to unsubscribe, it sends a gossip message to F randomly
selected accessible peers with its own unsubscription added to unSubs.
This happens whenever a node wants to unsubscribe, not during the
periodic gossip sending.



