Added ability to change time format string for when you're in System

Clock mode. Fixed code so that editing settings in the settings dialog
will now immediately take effect in the program.

mainwindow.h

@@ -97,6 +97,7 @@ private slots:
 public slots:
     void gotFrames(int);
     void updateSettings();
+    void readUpdateableSettings();
     void gotCenterTimeID(int32_t ID, double timestamp);
     void updateConnectionSettings(QString connectionType, QString port, int speed0, int speed1);
 
@@ -168,7 +169,6 @@ private:
     void killEmAll();
     void killWindow(QDialog *win);
     void readSettings();
-    void readUpdateableSettings();
     void writeSettings();
 };