moved stopwatch into Support namespace

OpenRa.Game/Support/Stopwatch.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Runtime.InteropServices;
+
+namespace OpenRa.Game.Support
+{
+	class Stopwatch
+	{
+		[DllImport("kernel32.dll")]
+		static extern bool QueryPerformanceCounter(out long value);
+		[DllImport("kernel32.dll")]
+		static extern bool QueryPerformanceFrequency(out long frequency);
+
+		long freq, start;
+
+		public Stopwatch()
+		{
+			QueryPerformanceFrequency(out freq);
+			QueryPerformanceCounter(out start);
+		}
+
+		public double ElapsedTime()
+		{
+			long current;
+			QueryPerformanceCounter(out current);
+
+			return (current - start) / (double)freq;
+		}
+
+		public void Reset()
+		{
+			QueryPerformanceCounter(out start);
+		}
+	}
+}