Network: added interface list item.

* Added BNetworkInterfaceListItem that can be used by interface protocol
  add-ons to represent their functionality in the list view.
* It will automatically update itself on changes, and will show the
  specified label, and address, if any, as well as indicate whether or
  not the family has been disabled (which doesn't work perfectly yet,
  as IFF_AUTO_CONFIGURED is on the interface level).
* Therefore, the interface list item will no longer show the address,
  but the type of the device instead.
* Introduced the BNetworkConfigurationListener interface that is used
  to broadcast network updates to.

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

@@ -10,9 +10,13 @@
 #include <image.h>
 #include <ListItem.h>
 #include <Resources.h>
+#include <String.h>
 #include <View.h>
 
 
+class BNetworkAddress;
+
+
 namespace BNetworkKit {
 
 
@@ -31,7 +35,14 @@ class BNetworkProfile;
 class BNetworkSettings;
 
 
-class BNetworkSettingsItem {
+class BNetworkConfigurationListener {
+public:
+	virtual void				ConfigurationUpdated(
+									const BMessage& message) = 0;
+};
+
+
+class BNetworkSettingsItem : public BNetworkConfigurationListener {
 public:
 								BNetworkSettingsItem();
 	virtual						~BNetworkSettingsItem();
@@ -73,6 +84,36 @@ private:
 };
 
 
+class BNetworkInterfaceListItem : public BListItem,
+	public BNetworkConfigurationListener {
+public:
+								BNetworkInterfaceListItem(int family,
+									const char* interface, const char* label,
+									BNetworkSettings& settings);
+								~BNetworkInterfaceListItem();
+
+	virtual	void				DrawItem(BView* owner,
+									BRect bounds, bool complete);
+	virtual	void				Update(BView* owner, const BFont* font);
+
+	virtual void				ConfigurationUpdated(const BMessage& message);
+
+private:
+			BFont				_AddressFont();
+			void				_UpdateState();
+
+private:
+			BNetworkSettings&	fSettings;
+			int					fFamily;
+			const char*			fInterface;
+			const char*			fLabel;
+			BString				fAddress;
+			bool				fDisabled;
+			float				fLineOffset;
+			float				fSpacing;
+};
+
+
 class BNetworkSettingsAddOn {
 public:
 								BNetworkSettingsAddOn(image_id image,