Add environ module and refactor unit handling
#790
| Job | Run time |
|---|---|
| 3m 10s | |
| 1m 49s | |
| 2m 43s | |
| 1m 32s | |
| 1m 53s | |
| 2m 54s | |
| 2m 0s | |
| 1m 47s | |
| 2m 42s | |
| 2m 2s | |
| 1m 54s | |
| 1m 56s | |
| 3m 31s | |
| 1m 54s | |
| 1m 57s | |
| 33m 44s |