Add jquery.uniform 1.80

Source files:
https://github.com/pixelmatrix/uniform/blob/master/jquery.uniform.min.js
https://github.com/pixelmatrix/uniform/blob/master/jquery.uniform.js
https://github.com/pixelmatrix/uniform/blob/master/themes/default/uniform.default.css

Images compressed from originals with tinypng:
https://github.com/pixelmatrix/uniform/blob/master/themes/default/images/bg-input-focus.png
https://github.com/pixelmatrix/uniform/blob/master/themes/default/images/bg-input.png
https://github.com/pixelmatrix/uniform/blob/master/themes/default/images/sprite.png