Complete install of OpenAI Gym learning environments

Not all environments are usable with the minimal installation. To be able to use most or all the environments available in the Gym, we will go through the installation of the dependencies and build OpenAI Gym from the latest source code on the master branch.

To get started, we will need to install the required system packages first. Next, you will find instructions for both Ubuntu and macOS. Choose the set of instructions based on your development platform.