use simple access field for some presets

* renamed access_toilet field to access_simple
* use it also for [parkings](http://taginfo.openstreetmap.org/tags/amenity=parking#combinations), [entrances](http://taginfo.openstreetmap.org/keys/entrance#combinations) and [swimming_pools](http://taginfo.openstreetmap.org/tags/leisure=swimming_pool#combinations)