DisplayManagerWin: fix mapping back our modes to DEVMODEs

isModeMatching() always returned false for modes which were not integers
(because of the "fudging" of the integer refresh rates in
DisplayManagerWin::initialize).

Apply a quick hack which should map them back correctly.

Completely untested.

src/display/win/DisplayManagerWin.cpp

@@ -206,7 +206,7 @@ bool DisplayManagerWin::isModeMatching(DEVMODEW& modeInfo, DMVideoModePtr videoM
     return false;
   if (videoMode->width != modeInfo.dmPelsWidth)
     return false;
-  if (videoMode->refreshRate != modeInfo.dmDisplayFrequency)
+  if ((int)(videoMode->refreshRate + 0.5f) != modeInfo.dmDisplayFrequency)
     return false;
   if (videoMode->bitsPerPixel != modeInfo.dmBitsPerPel)
     return false;