update pybullet docs, add getList to pybullet_envs

examples/pybullet/gym/pybullet_envs/__init__.py

@@ -132,3 +132,7 @@ register(
 	max_episode_steps=1000,
 	reward_threshold=2500.0
 	)
+
+def getList():
+	btenvs = ['- ' + spec.id for spec in gym.envs.registry.all() if spec.id.find('Bullet')>=0])
+	return btenvs