Step identifier other than title #117

We use localization for titles and some of the step titles are quite complicated (long with spaces, including accented characters and so on) to be used as an identifiers for the step (e.g. current-step attribute). I think it would be great to add some kind of ID which is NOT the title of the step and use it instead of the title to point to a step (e.g. in a goTo or current-step).

<wizard current-step="'continuing'"> 
    <wz-step title="Getting started" name="starting">
        ...
    </wz-step>
    <wz-step title="Continuing and so on" name="continuing">
        ...
    </wz-step>
</wizard>