unify CSRLinear, CSCLinear, COOLinear using SparseLinear
#251
| Job | Run time |
|---|---|
| 2m 10s | |
| 2m 13s | |
| 1m 54s | |
| 2m 3s | |
| 2m 15s | |
| 2m 18s | |
| 2m 3s | |
| 2m 20s | |
| 2m 1s | |
| 2m 15s | |
| 2m 6s | |
| 23m 38s |