retain a bit more precision in the timer

src/platform_w32_common/Timer.cpp

@@ -4,6 +4,7 @@ namespace Timer
 {
   LARGE_INTEGER LastPCV = { 0 } ;
   double currentTime = 0.0;
+  double startTime = 0.0;
 
   double _Time()
   {
@@ -21,13 +22,13 @@ namespace Timer
     return currentTime * 1000.0f;
   }
 
-  float startTime = 0.0;
   void Start()
   {
     startTime = (float)_Time();
   }
+
   float GetTime()
   {
-    return (float)_Time() - startTime;
+    return (float) ( _Time() - startTime );
   }
 }
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