Allow Event.emit to handle multiple arguments

[w33ble]

Our Event class was only handling a single argument on events, that is:

evented.emit('name', payload);
evented.on('name', function (payload) {})

This PR allows the use of multiple arguments in the emitters and handlers, like so:

evented.emit('name', item1, item2, item3);
evented.on('name', function (item1, item2, item3) {})

[spalger]

LGTM

[jbudz]

👍