change hasher's constants to signed (compared with signed)
change hasher's constants to signed (compared with signed)

royaltm/node-murmurhash-native,royaltm/node-murmurhash-native,royaltm/node-murmurhash-native,royaltm/node-murmurhash-native,royaltm/node-murmurhash-native,royaltm/node-murmurhash-native