Creates a radio button. This element must be used within CKForm or HTML form.
Required attributes: selection and value, or checked
|name:||Name that identifies the radio button’s group.|
|checked:||If neither "value" nor "selection" attribute is nil and the value of "selection" is equal to that of "value", the check box is checked.|
|value:||When the check box is checked, the value of "value" attribute is set to the component by the method specified by "selection" attribute.|
|selection:||Object that the user chose from the check box.|
|enabled:||If the value is true, the element appears but is not active.|