2016-01-06, Version 5.4.0 (Stable)

* http:
  - A new status code was added: 451 - "Unavailable For Legal Reasons"
(Max Barinov) https://github.com/nodejs/node/pull/4377
  - Idle sockets that have been kept alive now handle errors (José F.
Romaniello) https://github.com/nodejs/node/pull/4482
* This release also includes several minor performance improvements:
  - assert: deepEqual is now speedier when comparing TypedArrays
(Claudio Rodriguez) https://github.com/nodejs/node/pull/4330
  - lib: Use arrow functions instead of bind where possible (Minwoo
Jung) https://github.com/nodejs/node/pull/3622
  - node: Improved accessor perf of process.env (Trevor Norris)
https://github.com/nodejs/node/pull/3780
  - node: Improved performance of process.hrtime() (Trevor Norris)
https://github.com/nodejs/node/pull/3780, (Evan Lucas)
https://github.com/nodejs/node/pull/4484
  - node: Improved GetActiveHandles performance (Trevor Norris)
https://github.com/nodejs/node/pull/3780
  - util: Use faster iteration in util.form...