FormsyRadioGroup `defaultValue` with 0 does not work

[asafshen]

1. If you set defaultValue prop to a 0 value, the radio does not consider it as the component's value

<FormsyRadioGroup 
                          name="radioTest"
                          defaultSelected={0}
 >
              <FormsyRadio
                value={0}
                label="zero"
              />
              <FormsyRadio
                value={1}
                label="one"
              />
</FormsyRadioGroup>