Allow inline definitions of callbacks

Allows for callback definitions like this

```
Task = Ember.Object.extend(Ember.FSM.Stateful, {
  name: "",
  states: {
    "available.created": {
      willEnter: function(transition) {
        return console.log("created willEnter", this, transition);
      }
    }
  },
  stateEvents: {
    sCreate: {
      transition: {
        from: "$initial",
        to: "available.created",
        beforeEvent: function(transition) {
          return console.log("sCreate beforeEvent", this, transition);
        }
      }
    }
  }
});
```

Also note that

```
function() {
  return fn.apply(target, arguments);
};
```

is equivalent to `fn.bind(target)`

Thanks for your nice FSM implementation!