Code rewriting

The code (environment / ML) might not be the most beautiful. While rewriting it from scratch, the following aspects should be taken in account.

• Use only the metric system, everywhere ([JZ] I am not sure about the metric system. If we use it, we will have two systems in our code (metric/pixel). Maybe we should only use the pixel system, and then we write some converting function only for us the understand)
• Normalisation should only happen in one place
• PyGame should not be used to generate the observations (limited to 3 channels)
• Models musn't be saved because they cannot be saved (they are classes instantiations!)
• One file for all environments
• Do not return a tuple / list (use a dictionary instead)
• Display and observation rendering resolution must not be tied together
• Need to have a relative view as well (display only a neighbourhood around the ego car)
• [JZ] We shouldn't pass the opt object around. It is better to only pass what we need.