Get a better implementation of environment batching

[TheButlah]

We need an alternative to baselines's SubprocVecEnv. We don't need the entirety of baselines as a dependency, and the environments cannot be individually reset which is very important to our approach, as we want the batch size to remain the same size for convenience purposes and to avoid over fitting on longer episodes as smaller batches mean biased gradients.

[TheButlah]

I spent all of today working on this and have finished the implementation.