Reworked notification code in system tray.

Added a base class and a possibility for the main dialogs and the plugins (derived from MainPage) to provide a notifier.

git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@5381 b45a01b8-16f6-495d-af2f-9b41ad6348cc

retroshare-gui/src/retroshare-gui/mainpage.h

@@ -25,6 +25,7 @@
 
 #include <QWidget>
 
+class UserNotify;
 
 class MainPage : public QWidget
 {
@@ -33,6 +34,7 @@ public:
   MainPage(QWidget *parent = 0, Qt::WindowFlags flags = 0) : QWidget(parent, flags) {}
 
   virtual void retranslateUi() {}
+  virtual UserNotify *getUserNotify(QObject */*parent*/) { return NULL; }
 };
 
 #endif