Prevents duplicated event hooks.

Assets/Cryville/Crtr/InputProxy.cs

@@ -42,6 +42,7 @@ namespace Cryville.Crtr {
 			if (_use[proxy.Target] > 0)
 				throw new InvalidOperationException("Input already assigned");
 			if (proxy.Source != null) {
+				proxy.Source.Value.Handler.OnInput -= OnInput; // Prevent duplicated hooks, no exception will be thrown
 				proxy.Source.Value.Handler.OnInput += OnInput;
 				_tproxies.Add(proxy.Target, proxy);
 				_sproxies.Add(proxy.Source.Value, proxy);