Added support for saving and restoring the sensor history for the last 24h. The sensor history is now saved in a reduced format (duplicate values are removed, gaps are marked with a NAN sensor value.

GUI/MainForm.cs

@@ -501,12 +501,11 @@ namespace OpenHardwareMonitor.GUI {
     }
     
     private void MainForm_FormClosed(object sender, FormClosedEventArgs e) {
-      Visible = false;
-      SaveConfiguration();
-
+      Visible = false;      
       systemTray.IsMainIconEnabled = false;
       timer.Enabled = false;            
       computer.Close();
+      SaveConfiguration();
       systemTray.Dispose();
     }