Geoloc

A geolocation service.

I don't know if the function and features must be given like this, as parameters.
And all these "logic" must be really in the service ? I think that's good like this but I'm not sur.

Other things, Does this services must have a "remove" function to unbind all created events ?

Thanks to review.
This one is for a example a bit strange. If the user knows how to create an `ol.Geolocation` object, he also knows how to register a `change` listener on that object. So it does make sense to me to have this in the service.