mjpro and mujoco_py installation experience

[wweichn]

I have tried to install this on Mac and linux system. Here's my experience. The existed mjpro150 and corresponding mujoco_py 1.50 can't support this repo. Mac doesn't support mjpro131. So to run this, you need to install it on linux system. Choose mjpro131, mujoco_py 0.5.7, gym 0.7.4, then I met the problem Exception: glfw failed to initialize Fatal Python error: Couldn't create autoTLSkey mapping. Change main.py file, env.render() to 'env.render(600,600)', the environment can work.