Network: broadcast updates, remove apply button.

* Network now monitors all network, and network settings changes, and
  will notify all add-ons about those changes.
* Removed the global apply button. Instead, the static IP configuration
  now got that button. All other changes will be instant.

headers/os/add-ons/network_settings/NetworkSettingsAddOn.h

@@ -23,6 +23,10 @@ enum BNetworkSettingsType {
 	B_NETWORK_SETTINGS_TYPE_OTHER = 'othr'
 };
 
+enum {
+	kMsgSettingsItemUpdated = 'SIup'
+};
+
 class BNetworkProfile;
 class BNetworkSettings;
 
@@ -42,10 +46,12 @@ public:
 			const BNetworkProfile*
 								Profile() const;
 
-	virtual	status_t			Apply() = 0;
 	virtual	status_t			Revert() = 0;
 	virtual bool				IsRevertable() = 0;
 
+	virtual void				SettingsUpdated(uint32 type);
+	virtual void				ConfigurationUpdated(const BMessage& message);
+
 private:
 			const BNetworkProfile*
 								fProfile;