Introduce BlockIndices that generalizes BlockIndexRange to non-contiguous slicing
#605
| Job | Run time |
|---|---|
| 6s | |
| 12m 12s | |
| 5m 30s | |
| 11m 34s | |
| 16m 5s | |
| 9m 57s | |
| 13m 19s | |
| 1h 8m 43s |