refactor pybullet/gym to allow instantiating environments directly from a pybullet install:

work-in-progress (need to add missing data files, fix paths etc)

example:

pip install pybullet
pip install gym

python
import gym
import pybullet
import pybullet_envs
env = gym.make("HumanoidBulletEnv-v0")

examples/pybullet/gym/enjoy_TF_InvertedPendulumBulletEnv_v0_2017may.py

@@ -1,7 +1,7 @@
 import gym
 import numpy as np
 import pybullet as p
-import envs
+import pybullet_envs
 import time
 
 def relu(x):