Closes#1318
BREAKING CHANGE: $ionicActionSheet's default behavior is now to cancel
when the app's state changes. To disable this behavior, pass
`cancelOnStateChange: false` into $ionicActionSheet.show().
BREAKING CHANGE: $ionicActionSheet now returns a method to hide the
action sheet.
Previously, it returned an object that had a `show` and `hide` method.
This was undocumented, but if you used it, here is how to migrate your
code:
Change your code from this:
```js
var sheet = $ionicActionSheet.show({...});
sheet.hide();
```
To this:
```js
var hideSheet = $ionicActionSheet.show({...});
hideSheet();
```
