Remove GPS info from photos when geotagging is off.

Please review @astralbodies @koke 
So far this class doesn't keep any state so I'd rather use an extra parameter than a property. @astralbodies thoughts?
In any case, if this stays:
- this needs documentation
- it will default to `NO`, changing the current behavior. I'd flip it and use `stripGeolocation` so if you don't set the variable it will behave as it does right now.