Adding stat_names and support for row/col splits and `ContentRow` #442

All 215 tests pass in 1m 32s

1 files ±0 27 suites ±0 1m 32s ⏱️ -3s
215 tests ±0 215 ✅ ±0 0 💤 ±0 0 ❌ ±0
1 574 runs ±0 1 574 ✅ ±0 0 💤 ±0 0 ❌ ±0

Results for commit ed3c2e2. ± Comparison against earlier commit b8d065c.