Windows Disable ScreenSaver Train View

.. previously it was disabled via VLC, but if you're not running
   with video then the screensaver will kick in on Windows.

.. we now disable it via the Windows API too

Fixes #1859

src/Train/TrainSidebar.cpp

@@ -64,6 +64,10 @@
 #include <QStyleFactory>
 #endif
 
+#ifdef WIN32
+#include "Windows.h"
+#endif
+
 #include <cmath> // isnan and isinf
 #include "TrainDB.h"
 #include "Library.h"
@@ -1075,9 +1079,13 @@ void TrainSidebar::Start()       // when start button is pressed
 
         qDebug() << "start...";
 
+#ifdef WIN32
+        // disable the screen saver on Windows
+        SetThreadExecutionState(ES_DISPLAY_REQUIRED | ES_CONTINUOUS);
+#endif
+
         // Stop users from selecting different devices
         // media or workouts whilst a workout is in progress
-
 #if !defined GC_VIDEO_NONE
         mediaTree->setEnabled(false);
 #ifdef GC_HAVE_VLC  // RLV currently only support for VLC
@@ -1211,6 +1219,11 @@ void TrainSidebar::Stop(int deviceStatus)        // when stop button is pressed
 {
     if ((status&RT_RUNNING) == 0) return;
 
+    // re-enable the screen saver on Windows
+#ifdef WIN32
+    SetThreadExecutionState(ES_CONTINUOUS);
+#endif
+
     clearStatusFlags(RT_RUNNING|RT_PAUSED);
 
     // Stop users from selecting different devices