Test fail

Hello,

here is the result of mocha test:
```
$ mocha
big buffer echo (yawl):

Listening: http://localhost:9001
yawl
✓ fragmented messages with maxFrameSize Infinity (171ms)
1) maxFrameSize
✓ buffered messages (57ms)
✓ streaming messages (93ms)
✓ client emits error when server misb$ mocha
big buffer echo (yawl):

Listening: http://localhost:9001
yawl
✓ fragmented messages with maxFrameSize Infinity (171ms)
1) maxFrameSize
✓ buffered messages (57ms)
✓ streaming messages (93ms)
✓ client emits error when server misbehaves
2) allowUnfragmentedMessages = false
✓ send a ping and get a pong during a fragmented stream (135ms)
✓ parseExtensionList missing header
✓ parseExtensionList complicated
✓ parseExtensionList
✓ parseSubProtocolList
✓ client throws error for invalid protocol
3) client emits error when server hangs up
✓ client emits error when server responds with HTTP
✓ server requires explicitly setting origin
✓ negotiating fail
✓ negotiating succeed (133ms)
✓ invalid origin
✓ valid origin
✓ invalid websocket version
✓ invalid websocket key
✓ trying to send too big payloads

19 passing (5s)
3 failing

1) yawl
maxFrameSize:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
at Timeout. (/usr/lib/nodejs/mocha/lib/runnable.js:238:19)

2) yawl
allowUnfragmentedMessages = false:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
at Timeout. (/usr/lib/nodejs/mocha/lib/runnable.js:238:19)

3) yawl
client emits error when server hangs up:
Uncaught AssertionError [ERR_ASSERTION]: Input A expected to strictly equal input B:
+ expected - actual

- undefined
+ 'ECONNRESET'
at WebSocketClient. (test/test.js:429:16)
at ClientRequest.onResponse (index.js:173:12)
at HTTPParser.parserOnIncomingClient [as onIncoming] (_http_client.js:556:21)
at HTTPParser.parserOnHeadersComplete (_http_common.js:109:17)
at Socket.socketOnData (_http_client.js:442:20)
at addChunk (_stream_readable.js:284:12)
at readableAddChunk (_stream_readable.js:265:11)
at Socket.Readable.push (_stream_readable.js:220:10)
at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)ehaves
2) allowUnfragmentedMessages = false
✓ send a ping and get a pong during a fragmented stream (135ms)
✓ parseExtensionList missing header
✓ parseExtensionList complicated
✓ parseExtensionList
✓ parseSubProtocolList
✓ client throws error for invalid protocol
3) client emits error when server hangs up
✓ client emits error when server responds with HTTP
✓ server requires explicitly setting origin
✓ negotiating fail
✓ negotiating succeed (133ms)
✓ invalid origin
✓ valid origin
✓ invalid websocket version
✓ invalid websocket key
✓ trying to send too big payloads

19 passing (5s)
3 failing

1) yawl
maxFrameSize:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
at Timeout. (/usr/lib/nodejs/mocha/lib/runnable.js:238:19)

2) yawl
allowUnfragmentedMessages = false:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.
at Timeout. (/usr/lib/nodejs/mocha/lib/runnable.js:238:19)

3) yawl
client emits error when server hangs up:
Uncaught AssertionError [ERR_ASSERTION]: Input A expected to strictly equal input B:
+ expected - actual

- undefined
+ 'ECONNRESET'
at WebSocketClient. (test/test.js:429:16)
at ClientRequest.onResponse (index.js:173:12)
at HTTPParser.parserOnIncomingClient [as onIncoming] (_http_client.js:556:21)
at HTTPParser.parserOnHeadersComplete (_http_common.js:109:17)
at Socket.socketOnData (_http_client.js:442:20)
at addChunk (_stream_readable.js:284:12)
at readableAddChunk (_stream_readable.js:265:11)
at Socket.Readable.push (_stream_readable.js:220:10)
at TCP.onStreamRead [as onread] (internal/stream_base_commons.js:94:17)
```
Also test never ends: missing `httpServer.close()` somewhere