Cleanup imports.

Till now, most of the modules were importing all of the module objects
(variables, classes, functions, other imports) into module namespace,
which potentially could (and was) cause of unintentional use of class or
methods, which was indirect imported.

With this patch, all the star imports were substituted with top-level
module, which provides desired class or function.

Besides, all imports where sorted (where possible) in a way pep8[1]
suggests - first are imports from standard library, than goes third
party imports (like numpy, tensorflow etc) and finally coach modules.
All of those sections are separated by one empty line.

[1] https://www.python.org/dev/peps/pep-0008/#imports

environments/__init__.py

@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2017 Intel Corporation 
+# Copyright (c) 2017 Intel Corporation
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,15 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
-
-from logger import *
-from utils import Enum, get_open_port
-from environments.gym_environment_wrapper import *
-from environments.doom_environment_wrapper import *
-from environments.carla_environment_wrapper import *
+from environments.gym_environment_wrapper import GymEnvironmentWrapper
+from environments.doom_environment_wrapper import DoomEnvironmentWrapper
+from environments.carla_environment_wrapper import CarlaEnvironmentWrapper
+import utils
 
 
-class EnvTypes(Enum):
+class EnvTypes(utils.Enum):
     Doom = "DoomEnvironmentWrapper"
     Gym = "GymEnvironmentWrapper"
     Carla = "CarlaEnvironmentWrapper"
@@ -31,6 +29,3 @@ def create_environment(tuning_parameters):
     env_type_name, env_type = EnvTypes().verify(tuning_parameters.env.type)
     env = eval(env_type)(tuning_parameters)
     return env
-
-
-