Added an option to control whether or not node-ipc unlinks the Unix
socket path when it starts a server which, when set to false, allows the
overall application to handle this and allows node-ipc to work with the
Node.js cluster module.
Make sure the entire process doesn't crash when a message is sent without `type` and/or `data` as such:
```
error: Uncaught Exception TypeError: Cannot read property 'id' of undefined
at Server.gotData (/usr/src/app/node_modules/@trail/pigeoneer/node_modules/node-ipc/dao/socketServer.js:181:24)
at emitOne (events.js:101:20)
at Socket.emit (events.js:188:7)
at Socket.EventEmitter.emit (/usr/src/app/node_modules/@trail/pigeoneer/node_modules/sc-domain/index.js:12:31)
at readableAddChunk (_stream_readable.js:176:18)
at Socket.Readable.push (_stream_readable.js:134:10)
at TCP.onread (net.js:548:20)
```
