Improvement for radio buttons

[MollsAndHersh]

Hello.

Just wanted to pass this along... I needed to be able to allow radio buttons to be shown as disabled in some circumstances.

This capability seems to be missing from the latest commit, so I just wanted to pass along the quick change that I made, so that perhaps you might want to add it permanently to the repo.

Hopes this helps someone else.

Regards,

Mark Chipman