Merge pull request #901 from Unity-Technologies/hotfix-swish

Replace CC `tanh` activation with `swish`

python/trainer_config.yaml

 
 Ball3DBrain:
     normalize: true
-    batch_size: 1200
+    batch_size: 64
+    lambd: 0.99
     gamma: 0.995
     beta: 0.001
 

python/unitytrainers/models.py

         :return: List of encoded streams.
         """
         brain = self.brain
-        if brain.vector_action_space_type == "continuous":
-            activation_fn = tf.nn.tanh
-        else:
-            activation_fn = self.swish
+        activation_fn = self.swish
 
         self.visual_in = []
         for i in range(brain.number_visual_observations):