Sky Checkbox does not have the proper styles when it is both checked and disabled

[Blackbaud-LuisBello]

When using the Sky checkbox component, if you check and disable the checkbox, it looks no different than when it is checked and active; You still see just the check mark with a blue background color, as if the checkbox was still active. Proper behavior should be that you see the check mark with a gray background color, the same one when it's disabled and unchecked.

[Blackbaud-PatrickOFriel]

In 2.0.0-alpha.9

Using sky-pages, we still have the problem of all font-awesome icons (in this case check) appearing as boxes so that may still affect you.