Changes Environment.obs_space and Environment.action_space from class to instance methods. Also removes the env_cls method on VecEnv in favor of obs_space and action_space methods. This makes it much easier to create environment wrappers, environments where the action/observation space depend on configuration, and VecEnv implementations which don't have an underlying Environment class.
Changes
Environment.obs_spaceandEnvironment.action_spacefrom class to instance methods. Also removes theenv_clsmethod onVecEnvin favor ofobs_spaceandaction_spacemethods. This makes it much easier to create environment wrappers, environments where the action/observation space depend on configuration, andVecEnvimplementations which don't have an underlyingEnvironmentclass.