Add feature to CheckBoxRadio Widget - DE-selection.

Add feature to CheckBoxRadio Widget - DE-selection.

Hello! I'm currently working on an app that uses the checkboxradio widget; however, the requirement for being able to retract a selection cannot be currently fulfilled. Are there any plans to implement a de-selection feature where a user may "clear" the selected radio button without refreshing the control? If there are no plans to implement, would a pull request to implement this change be likely accepted? Thanks in advance!