Race issue in bitballs

In bitballs, there's a `` two-way bound to `team`-that-is-being-created's `color`:

```html

{{# each(availableColors) }}
{{ . }}
{{/ each }}

```

There's a bug where
1. `can-connect` is adding the newly created team to the list of teams.
2. `availableColors` changes, which causes a mutation,
3. Removing the newly created color from the list of options.
4. which updates the `team`-that-is-being-created's `color`

This all happens before the `team`-that-is-being-created is replaced by a new Team:

```js
this.teamSavePromise = this.team.save(function(){
self.team = new Team();
});
```

This "race" condition changes because of zones. Without zones, the mutation happens after the promise is resolved. With zones, the mutation fires before the zone fires.