Does not run with latest baselines (0.1.5)

[swenner]

python3 main.py CartPole-v1 --render
Traceback (most recent call last):
  File "main.py", line 35, in 
    venv = RenderSubprocVecEnv(env_fns, args.render_interval)
TypeError: Can't instantiate abstract class RenderSubprocVecEnv with abstract methods step_async, step_wait