Fix misleading propTypes error when no localizer configured
Fix misleading propTypes error when no localizer configured

react-widgets is designed to throw an error if you try to use certain
functionality when no localizer is configured. However, it didn't check
"propType," so the propType validation function was undefined, resulting
in React's propTypes validator throwing confusing messages like

Warning: Failed propType: Cannot read property 'apply' of
undefined Check the render method of `Uncontrolled(NumberPicker)`.

haneev/react-widgets,jquense/react-widgets,jquense/react-widgets,haneev/react-widgets,jquense/react-widgets