Add wildcard support for events

It would be great if you could use a wildcard to capture all events. For example:

client.on("*", function(data) {

}

[mkhahani]

It can be handled in the app logic using one event name for all events:

socket.emit('public-event', {'type': 'login', ...});
socket.emit('public-event', {'type': 'logout', ...});

[alexey-sh]

how it’s going? +1 for on("*", function () { for both client and server