Switch the Gym automated logger setup to configure the root logger rather than just the 'gym' logger

Python doesn't make it easy for libraries to take responsibility for
logging configuration (which we do to make simple usage much easier),
and as we see more Gym plugins, we want their loggers to have an
appropriate log level too. So we may as well configure the root logger
level.

examples/agents/random_agent.py

@@ -1,5 +1,7 @@
+import argparse
 import logging
-import os, sys
+import os
+import sys
 
 import gym
 
@@ -12,13 +14,25 @@ class RandomAgent(object):
         return self.action_space.sample()
 
 if __name__ == '__main__':
-    # You can optionally set up the logger. Also fine to set the level
-    # to logging.DEBUG or logging.WARN if you want to change the
-    # amount of output.
+    parser = argparse.ArgumentParser(description=None)
+    parser.add_argument('env_id', nargs='?', default='CartPole-v0', help='Select the environment to run')
+    args = parser.parse_args()
+
+    # Call `undo_logger_setup` if you want to undo Gym's logger setup
+    # and configure things manually. (The default should be fine most
+    # of the time.)
+    gym.undo_logger_setup()
     logger = logging.getLogger()
+    formatter = logging.Formatter('[%(asctime)s] %(message)s')
+    handler = logging.StreamHandler(sys.stderr)
+    handler.setFormatter(formatter)
+    logger.addHandler(handler)
+
+    # You can set the level to logging.DEBUG or logging.WARN if you
+    # want to change the amount of output.
     logger.setLevel(logging.INFO)
 
-    env = gym.make('CartPole-v0' if len(sys.argv)<2 else sys.argv[1])
+    env = gym.make(args.env_id)
 
     # You provide the directory to write to (can be an existing
     # directory, including one with existing data -- all monitor files