mxcl/PromiseKit — pull request #58 by nyankichi820 (2014-07-11 09:57:39+00:00)
Title: add Promise for UIAnimation.

Hello.
add Promise for UIAnimation.

Like this

```
__weak typeof(self) weakSelf = self;
dispatch_promise_on(dispatch_get_main_queue(),^{
return [UIView promiseAnimationWithDuration:0.2
animations:^{
weakSelf.label1.x = 500;

}];
}).then(^(BOOL finished){
return [UIView promiseAnimationWithDuration:0.2 animations:^{
weakSelf.label2.y = 600;

}];
}).then(^(BOOL finished){
return [UIView promiseAnimationWithDuration:0.2 animations:^{
weakSelf.label3.y = -100;

}];

})
```
please check.