Merge pull request #128 from UnityTech/yczhang

Change defaultMinTargetRate to 25

Runtime/ui/window.cs

         }
 
         public const int defaultMaxTargetFrameRate = 60;
-        public const int defaultMinTargetFrameRate = 15;
+        public const int defaultMinTargetFrameRate = 25;
 
         static Action _onFrameRateSpeedUp = defaultFrameRateSpeedUp;