Test for bbox coords only within swiss extent

This test is only valid for swiss extent.

At the moment, we have a bug
http://map.geo.admin.ch/main/rest/services/kgs/SearchServer?type=locations&searchText=gen&features=ch.babs.kulturgueter&timeEnabled=false&bbox=-204000,-191750.00000000006,1044000,320449.99999999994&lang=fr

This solves this issue.