Add PricesBase.to_csv to export prices to csv, also various fixes
#350
| Job | Run time |
|---|---|
| 32m 11s | |
| 31m 49s | |
| 20s | |
| 32m 4s | |
| 31m 58s | |
| 31m 49s | |
| 31m 51s | |
| 3h 12m 2s |