Deprecate style options - TextInput

Hi all

I add css rules for negating a style option.

data-corners

![image](https://cloud.githubusercontent.com/assets/3013966/3579372/aaf4909e-0bbd-11e4-92c3-69f81a5689cd.png)


This PR require #7464 in order to work properly.
If there are any problems or mistakes on that PR, please let me know. Thanks in advance.

Fixes gh-7303
This should go under tests/css/textinput/.