Country Javascript throbber. Use display instead of background style

Hi,

Today, I wanted to theme the address selection system, and I noticed that the throbber animation for ajax loading is hard coded in uc_country_select.js file.

I think it's better to use display CSS property instead of directly put the background image, it would allow developper to theme the throbber.gif animation, for the case, like me, where the background is dark and need another throbber.gif file.

This patch add a display:block property when country is selected, so you can define the throbber gif to load in the CSS, and so, it's overwritable by custom CSS.

you have to add a CSS rule to uc_store.css too :

 .zone-throbber { display:none; background:url(../../../../../misc/throbber.gif) no-repeat 0px -18px; }