fix on the CoreBrains so that if one Corebrain gets eraised, it will be reinstanciated

unity-environment/Assets/ML-Agents/Scripts/Brain.cs

             }
 
         }
+        else
+        {
+            foreach (BrainType bt in System.Enum.GetValues(typeof(BrainType)))
+            {
+                if ((int)bt >= CoreBrains.Length)
+                    break;
+                if (CoreBrains[(int)bt] == null)
+                {
+                    CoreBrains[(int)bt] = ScriptableObject.CreateInstance("CoreBrain" + bt.ToString());
+                }
+            }
+        }
 
         // If the length of CoreBrains does not match the number of BrainTypes, 
         // we increase the length of CoreBrains
         foreach (KeyValuePair<int, Agent> idAgent in agents)
         {
             List<float> states = idAgent.Value.CollectState();
-            if ((states.Count != brainParameters.stateSize) && (brainParameters.stateSpaceType == StateType.continuous ))
+            if ((states.Count != brainParameters.stateSize) && (brainParameters.stateSpaceType == StateType.continuous))
-            if ((states.Count != 1) && (brainParameters.stateSpaceType == StateType.discrete ))
+            if ((states.Count != 1) && (brainParameters.stateSpaceType == StateType.discrete))
             {
                 throw new UnityAgentsException(string.Format(@"The number of states does not match for agent {0}:
     Was expecting 1 discrete states but received {1}.", idAgent.Value.gameObject.name, states.Count));