What features should we have for the StarCraft 2 Environment?

[alvarofpp]

We must define what is and isn't possible for the StarCraft 2 Environment class. Some points I thought of:

• Map: we must ensure that the map defined is a valid map or not.
• Observation: pysc2 allows you to extract different observation layers, as listed in the official document. We should make it possible for all layers to be accessed easily.

In the end, we should create an issue with the specifications defined in this discussion.