increase plane from 30 to 200 (to allow quadrupeds to run further, not fall off cliff)

fix issue with gym.wrappers in pybullet_envs.agents.visualize_ppo.py

examples/pybullet/gym/pybullet_envs/agents/visualize_ppo.py

@@ -26,6 +26,7 @@ from __future__ import print_function
 import os
 
 import gym
+from gym import wrappers
 import tensorflow as tf
 
 from . import tools