Fixed variable key string being null

Assets/Fungus/VisualScripting/FungusScript.cs

@@ -96,7 +96,8 @@ namespace Fungus.Script
 				bool collision = false;
 				foreach(FungusVariable variable in GetComponents<FungusVariable>())
 				{
-					if (variable == ignoreVariable)
+					if (variable == ignoreVariable ||
+					    variable.key == null)
 					{
 						continue;
 					}

Assets/Fungus/VisualScripting/FungusVariable.cs

@@ -21,6 +21,6 @@ namespace Fungus.Script
 	public class FungusVariable : MonoBehaviour
 	{
 		public VariableScope scope;
-		public string key;
+		public string key = "";
 	}
 }