fix button height issue

Fixed issue where the X and down arrow button height is shorter than the input box.  Also slightly adjust the X box down so that it's vertically centered.

Tested on Chrome, Safari and IE 9

BEFORE
=======
![height](https://f.cloud.github.com/assets/313176/5175/99973c60-4356-11e2-972b-5d55bd7b1d46.png)

AFTER
=====
![Screen Shot 2012-12-10 at 11 51 03 PM](https://f.cloud.github.com/assets/313176/5176/d18f43c4-4356-11e2-9849-270b31ac536f.png)