Installation instructions could be clearer

[motiwari]

I think there were a few non-obvious pitfalls during the installation, that could be made clearer in the readme:

1. the baselines package must be installed per the instructions at https://github.com/openai/baselines, NOT via pip install baselines

2. rllab must be downloaded from https://github.com/rll/rllab and added to the PYTHONPATH, do NOT run setup.py install from inside the repo otherwise the setup_mujoco.sh will not run correctly because it won't install mujoco for rllab in the correct site-packages subdirectory

3. When running setup_mujoco.sh from the rllab repo, you must run it from the root of the repo and NOT the scripts folder due to the use of relative filepaths

4. cmake might need to be upgraded on the newest version of OSX (via brew upgrade cmake) for mujoco, and

Some of these are rllab issues, but rllab is no longer under active development so I wanted to catalog these issues here for posterity

[gavenma]

Thanks so much for your inputs. Couldn't have made it work without the heads up. The readme section should have been clearer!