I'm not sure the source, but `statusLabel.textColor` is no longer updating to green and red based on the account creation's success. @andrask, any idea?

Once it gets working, it'd be nice to simplify the updating of `statusLabel.textColor` into a single signal, as opposed to the current RAC-binding and [side-effect `subscribeOn:`][so]. Perhaps something like this:

```objc
RAC(self.statusLabel, textColor) = [RACSignal
                                    if:executing
                                    then:[RACSignal return:UIColor.lightGrayColor]
                                    else:[networkResults map:^id(RACEvent *x) {
                                        return x.eventType == RACEventTypeError ? UIColor.redColor
                                                                                : UIColor.greenColor;
                                    }]];
```

[so]: https://github.com/andrask/RACMobiDevDay/blob/3b81d248d6f8bcdb0f16206622edcb5047c18124/RACMobiDevDay/SignUpViewController.m#L75-L78