Metric and environment animation are out of sync

As of now, the metric and environment rendering is not in sync. That refers to the schedule, not to the fps or something like this. The latter seems fine. Metric animation schedule is based on episodes, while environment rendering is based on epochs. Though, both schedules would need some improvements.

We discussed in #118 (closed) that it would be nice to always render just the first episode of every nth epoch. So, that would be related to this issue.