Fix error on default props but no propTypes

[theogravity]

This fixes a bug where the styleguide does not display when you have a default prop defined but no proptypes:

propTypes: {
    someValue: 1
}

getDefaultProps() {
    return {
        someValue: 0
        someOtherValue: 1
    }
}

In the above case, someOtherValue would cause the guide to break because it is not in the propTypes. I have situations where I want to do this.

[pocotan001]

Thanks @theogravity !

[theogravity]

Thanks! May I ask when a new version will be published with the changes?