package.json: bump nan to latest for iojs build compatibility
package.json: bump nan to latest for iojs build compatibility

alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,jut-io/node-kafka-native,alfred-landrum/node-kafka-native,alfred-landrum/node-kafka-native