Merge pull request #35 from HypGamesOrlando/polling_alloc_fix

Fix to remove a per-frame allocation causing garbage collects

Author: ryzngard

plug-ins/Apple.GameController/Apple.GameController_Unity/Assets/Apple.GameController/Source/Controller/GCController.cs

@@ -175,10 +175,12 @@ public GCBatteryState GetBatteryState()
 
         public void Poll()
         {
-            _previousButtonPressStates = new Dictionary<GCControllerInputName, bool>(_buttonPressStates);            
-            foreach (var key in _buttonPressStates.Keys.ToList())
+            _previousButtonPressStates.Clear();
+            foreach (var kv in _buttonPressStates)
             {
-                _buttonPressStates[key] = false;
+                _previousButtonPressStates.Add(kv.Key, kv.Value);
+                _buttonPressStates[kv.Key] = false;
+
             }
 
             InputState = IsConnected ? GCControllerService.PollController(Handle) : GCControllerInputState.None;
@@ -191,4 +193,5 @@ public void SetLightColor(float red, float green, float blue)
             GCControllerService.SetControllerLightColor(Handle, red, green, blue);
         }
     }
-} 
+} 
+