Release v0.5 delete unityagents (#1151)

* fixed the loggers

* Modified the documentation

docs/Training-on-Amazon-Web-Service.md

 7. Test the instance setup from Python using:
 
     ```python
-    from unityagents import UnityEnvironment
+    from mlagents.envs import UnityEnvironment
 
     env = UnityEnvironment(<your_env>)
     ```
     //cd into your ml-agents/python folder
     chmod +x <your_env>.x86_64
     python learn.py <your_env> --train
-    ```
+    ```

docs/Training-on-Microsoft-Azure.md

 7. Test the instance setup from Python using:
 
 ```python
-from unityagents import UnityEnvironment
+from mlagents.envs import UnityEnvironment
 
 env = UnityEnvironment(<your_env>)
 ```

ml-agents/mlagents/trainers/bc/policy.py

 from mlagents.trainers.bc.models import BehavioralCloningModel
 from mlagents.trainers.policy import Policy
 
-logger = logging.getLogger("unityagents")
+logger = logging.getLogger("mlagents.trainers")
 
 
 class BCPolicy(Policy):

ml-agents/mlagents/trainers/policy.py

 from mlagents.trainers import UnityException
 from mlagents.trainers.models import LearningModel
 
-logger = logging.getLogger("unityagents")
+logger = logging.getLogger("mlagents.trainers")
 
 
 class UnityPolicyException(UnityException):

ml-agents/mlagents/trainers/ppo/policy.py

 from mlagents.trainers.ppo.models import PPOModel
 from mlagents.trainers.policy import Policy
 
-logger = logging.getLogger("unityagents")
+logger = logging.getLogger("mlagents.trainers")
 
 
 class PPOPolicy(Policy):