Bump version: 1.38 → 1.39

Bump version: 1.37 → 1.38

Bump version: 1.36 → 1.37

Bump version: 1.35 → 1.36

Bump version: 1.34 → 1.35

Bump version: 1.33 → 1.34

Bump version: 1.32 → 1.33

version: 1.32

better merge error messages

version: 1.31

better merge error messages

version: 1.30

make MergeOperation more easily overridable