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.
I recommend using `on('change:position', …)` as indicated in some previous comments of mine.