FLUID-5457, FLUID-5469: Remove FSS

Removed FSS. The fss directory in the prefs framework is still there and will be addressed by [FLUID-5482](http://issues.fluidproject.org/browse/FLUID-5482)
http://issues.fluidproject.org/browse/FLUID-5469

Also adds a fix for FLUID-5457, which allows for the cross to appear when using a custom default theme.
http://issues.fluidproject.org/browse/FLUID-5457
What I was thinking was to have a boolean model value to track the selected state of the container. "onSelect" handler only sets the model value to true while "onUnselect" sets the value to false. The actual functionality of onSelect and onUnselect handlers that you have here can be moved into the model listener. This way, the selected state is exposed to the end user of the component, which makes it easier to manipulate onSelect or onUnselect handlers via model listeners. What do you think?