Enable WebKit sandboxing on the OSM login verification dialog
The verification of OpenStreetMap account login (for editing POIs) shows a verification code from an HTML response in a web view (in osmAccountDialog.js). The WebKitWebView can now be set to use sandboxing (for security). Currently this view is setup directly in the .ui file. To be able to enable sandboxing, unfortunatly the view needs to be created programmatically in the dialog's _init() method. By constructing a WebKitWebContext instance, setting enabled sandbox on it and then create the view with webkit_web_view_new_with_context() and add the view to the dialog from code.