core: make nm-properties-changed-signal always export the right properties

Change the way that nm-properties-changed-signal works, and parse the
dbus-binding-tool-generated info to get the exact list of properties
that it's expected to export.

This makes NM_PROPERTY_PARAM_NO_EXPORT unnecessary, and also fixes the
problem of properties like NMDevice:hw-address being exported on
classes where it shouldn't be.

src/nm-activation-request.h

@@ -42,8 +42,6 @@ typedef struct {
 typedef struct {
 	NMActiveConnectionClass parent;
 
-	/* Signals */
-	void (*properties_changed) (NMActRequest *req, GHashTable *properties);
 } NMActRequestClass;
 
 GType nm_act_request_get_type (void);