Fix memory leak that's been there for 5 years but nobody noticed unti…

…l now :) Fixes #3.

XInputDotNetPure/GamePad.cs

@@ -336,6 +336,7 @@ public static GamePadState GetState(PlayerIndex playerIndex, GamePadDeadZone dea
             IntPtr gamePadStatePointer = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(GamePadState.RawState)));
             uint result = Imports.XInputGamePadGetState((uint)playerIndex, gamePadStatePointer);
             GamePadState.RawState state = (GamePadState.RawState)Marshal.PtrToStructure(gamePadStatePointer, typeof(GamePadState.RawState));
+            Marshal.FreeHGlobal(gamePadStatePointer);
             return new GamePadState(result == Utils.Success, state, deadZone);
         }