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/carla_environment_wrapper.py

@@ -1,34 +1,31 @@
+import logging
+import os
+import signal
+import subprocess
 import sys
-from os import path, environ
-
-try:
-    if 'CARLA_ROOT' in environ:
-        sys.path.append(path.join(environ.get('CARLA_ROOT'), 'PythonClient'))
-    from carla.client import CarlaClient
-    from carla.settings import CarlaSettings
-    from carla.tcp import TCPConnectionError
-    from carla.sensor import Camera
-    from carla.client import VehicleControl
-except ImportError:
-    from logger import failed_imports
-    failed_imports.append("CARLA")
 
 import numpy as np
-import time
-import logging
-import subprocess
-import signal
-from environments.environment_wrapper import EnvironmentWrapper
-from utils import *
-from logger import screen, logger
-from PIL import Image
+
+import logger
+try:
+    if 'CARLA_ROOT' in os.environ:
+        sys.path.append(os.path.join(os.environ.get('CARLA_ROOT'),
+                                     'PythonClient'))
+    from carla import client as carla_client
+    from carla import settings as carla_settings
+    from carla import sensor as carla_sensor
+except ImportError:
+    logger.failed_imports.append("CARLA")
+from environments import environment_wrapper as ew
+import utils
 
 
 # enum of the available levels and their path
-class CarlaLevel(Enum):
+class CarlaLevel(utils.Enum):
     TOWN1 = "/Game/Maps/Town01"
     TOWN2 = "/Game/Maps/Town02"
 
+
 key_map = {
     'BRAKE': (274,),  # down arrow
     'GAS': (273,),  # up arrow
@@ -41,16 +38,16 @@ key_map = {
 }
 
 
-class CarlaEnvironmentWrapper(EnvironmentWrapper):
+class CarlaEnvironmentWrapper(ew.EnvironmentWrapper):
     def __init__(self, tuning_parameters):
-        EnvironmentWrapper.__init__(self, tuning_parameters)
+        ew.EnvironmentWrapper.__init__(self, tuning_parameters)
 
         self.tp = tuning_parameters
 
         # server configuration
         self.server_height = self.tp.env.server_height
         self.server_width = self.tp.env.server_width
-        self.port = get_open_port()
+        self.port = utils.get_open_port()
         self.host = 'localhost'
         self.map = CarlaLevel().get(self.tp.env.level)
 
@@ -70,7 +67,7 @@ class CarlaEnvironmentWrapper(EnvironmentWrapper):
                 self.settings = fp.read()
         else:
             # hard coded settings
-            self.settings = CarlaSettings()
+            self.settings = carla_settings.CarlaSettings()
             self.settings.set(
                 SynchronousMode=True,
                 SendNonPlayerAgentsInfo=False,
@@ -80,7 +77,7 @@ class CarlaEnvironmentWrapper(EnvironmentWrapper):
             self.settings.randomize_seeds()
 
             # add cameras
-            camera = Camera('CameraRGB')
+            camera = carla_sensor.Camera('CameraRGB')
             camera.set_image_size(self.width, self.height)
             camera.set_position(200, 0, 140)
             camera.set_rotation(0, 0, 0)
@@ -92,7 +89,7 @@ class CarlaEnvironmentWrapper(EnvironmentWrapper):
         logging.disable(40)
 
         # open the client
-        self.game = CarlaClient(self.host, self.port, timeout=99999999)
+        self.game = carla_client.CarlaClient(self.host, self.port, timeout=99999999)
         self.game.connect()
         scene = self.game.load_settings(self.settings)
 
@@ -141,12 +138,12 @@ class CarlaEnvironmentWrapper(EnvironmentWrapper):
             self.renderer.create_screen(image.shape[1], image.shape[0])
 
     def _open_server(self):
-        log_path = path.join(logger.experiments_path, "CARLA_LOG_{}.txt".format(self.port))
+        log_path = os.path.join(logger.logger.experiments_path, "CARLA_LOG_{}.txt".format(self.port))
         with open(log_path, "wb") as out:
-            cmd = [path.join(environ.get('CARLA_ROOT'), 'CarlaUE4.sh'), self.map,
-                                  "-benchmark", "-carla-server", "-fps=10", "-world-port={}".format(self.port),
-                                  "-windowed -ResX={} -ResY={}".format(self.server_width, self.server_height),
-                                  "-carla-no-hud"]
+            cmd = [os.path.join(os.environ.get('CARLA_ROOT'), 'CarlaUE4.sh'), self.map,
+                   "-benchmark", "-carla-server", "-fps=10", "-world-port={}".format(self.port),
+                   "-windowed -ResX={} -ResY={}".format(self.server_width, self.server_height),
+                   "-carla-no-hud"]
             if self.config:
                 cmd.append("-carla-settings={}".format(self.config))
             p = subprocess.Popen(cmd, stdout=out, stderr=out)
@@ -201,7 +198,7 @@ class CarlaEnvironmentWrapper(EnvironmentWrapper):
             action = action_idx
         self.last_action_idx = action
 
-        self.control = VehicleControl()
+        self.control = carla_client.VehicleControl()
         self.control.throttle = np.clip(action[0], 0, 1)
         self.control.steer = np.clip(action[1], -1, 1)
         self.control.brake = np.abs(np.clip(action[0], -1, 0))