Rejigger icons

The icons.less was imported into the style sheet, but it doesn't show on the demo page. I've added a link to the font-awesome.less file in the demo.html

Should the icons.less import be removed from the ui-input.less?

Also changed the icon structure from an attribute to an element in the lightdom. This added a lot of flexibility and also removed problems with the [icon=xyz] styles that collided with declaration of the icons on the parent element(also [icon=xyz]).

The spin animation doesn't seem to work, but the problem is that it appears to be left out of ui-font-awesome.