bump nan to 2.3.3 to fix node 6 compat
bump nan to 2.3.3 to fix node 6 compat

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