Add route to setUrlToElem for allowing custom IDs

The ability to override ```getIdFromElem``` isn't useful without also override
```setIdToElem``` as well. Since ```setIdToElem``` is called from ```one()``` before the
```.route``` value is added, adding a ```route``` parameter lets a consumer override
the setter function and use the route to build the ID.  Here's an
example of how this would be used:

```javascript
sr.configuration.setIdToElem = function (elem, value, route) {
route = route || elem.route;
elem[_.initial(route).join('') + "ID"] = value;
};
```