Feature/add subtitles to textfields

![screen shot 2014-12-08 at 23 03 06](https://cloud.githubusercontent.com/assets/57446/5348237/63a5f928-7f2e-11e4-921e-a04f34bf41b1.PNG)

Why killing the popover? `if (self.popoverController) self.popoverController = nil;`