crash when uploading large file

```
web socket error: Error: write EPIPE
at errnoException (net.js:905:11)
at Object.afterWrite (net.js:721:19)
Error: Request aborted
at IncomingMessage.onReqAborted (/home/josh/dev/groovebasin/node_modules/multiparty/index.js:183:17)
at IncomingMessage.emit (events.js:92:17)
at abortIncoming (http.js:1912:11)
at CleartextStream.serverSocketCloseListener (http.js:1924:5)
at CleartextStream.emit (events.js:117:20)
at tls.js:694:10
at process._tickCallback (node.js:448:13)

http.js:690
throw new Error('Can\'t set headers after they are sent.');
^
Error: Can't set headers after they are sent.
at ServerResponse.OutgoingMessage.setHeader (http.js:690:11)
at ServerResponse.header (/home/josh/dev/groovebasin/node_modules/express/lib/response.js:695:10)
at ServerResponse.send (/home/josh/dev/groovebasin/node_modules/express/lib/response.js:146:12)
at ServerResponse.json (/home/josh/dev/groovebasin/node_modules/express/lib/response.js:235:15)
at /home/josh/dev/groovebasin/lib/server.js:383:18
at cbListener (/home/josh/dev/groovebasin/node_modules/pend/index.js:49:5)
at Array.forEach (native)
at onCb (/home/josh/dev/groovebasin/node_modules/pend/index.js:45:17)
at /home/josh/dev/groovebasin/lib/server.js:367:11
at /home/josh/dev/groovebasin/lib/player.js:1138:11
```

(I'm not sure if that first part is relevant because there's no timestamps.)

I was uploading a 700MB zip of flac files.