Notable changes:
* events: Added EventEmitter#listenerCount(event) as a replacement for
EventEmitter.listenerCount(emitter, event), which has now been
marked as deprecated in the docs. (Sakthipriyan Vairamani) #2349
* module: Fixed an error with preloaded modules when the current
working directory doesn't exist. (Bradley Meck) #2353
* node: Startup time is now about 5% faster when not passing V8 flags.
(Evan Lucas) #2483
* repl: Tab-completion now works better with arrays.
(James M Snell) #2409
* string_bytes: Fixed an unaligned write in the handling of UCS2
encoding. (Fedor Indutny) #2480
* tls: Added a new --tls-cipher-list flag that can be used to override
the built-in default cipher list. (James M Snell) #2412
PR-URL: https://github.com/nodejs/node/pull/2512
* **events**: Added `EventEmitter#listenerCount(event)` as a replacement for `EventEmitter.listenerCount(emitter, event)`, which has now been marked as deprecated in the docs. (Sakthipriyan Vairamani) [#2349](https://github.com/nodejs/node/pull/2349)
* **module**: Fixed an error with preloaded modules when the current working directory doesn't exist. (Bradley Meck) [#2353](https://github.com/nodejs/node/pull/2353)
* **node**: Startup time is now about 5% faster when not passing V8 flags. (Evan Lucas) [#2483](https://github.com/nodejs/node/pull/2483)
* **repl**: Tab-completion now works better with arrays. (James M Snell) [#2409](https://github.com/nodejs/node/pull/2409)
* **string_bytes**: Fixed an unaligned write in the handling of UCS2 encoding. (Fedor Indutny) [#2480](https://github.com/nodejs/node/pull/2480)
* **tls**: Added a new `--tls-cipher-list` flag that can be used to override the built-in default cipher list. (James M Snell) [#2412](https://github.com/nodejs/node/pull/2412) _Note: it is suggested you use the built-in cipher list as it has been carefully selected to reflect current security best practices and risk mitigation._
### Known issues
See https://github.com/nodejs/io.js/labels/confirmed-bug for complete and current list of known issues.
* Some uses of computed object shorthand properties are not handled correctly by the current version of V8. e.g. `[{ [prop]: val }]` evaluates to `[{}]`. [#2507](https://github.com/nodejs/node/issues/2507)
* Some problems with unreferenced timers running during `beforeExit` are still to be resolved. See [#1264](https://github.com/nodejs/io.js/issues/1264).
* Surrogate pair in REPL can freeze terminal. [#690](https://github.com/nodejs/io.js/issues/690)
* `process.send()` is not synchronous as the docs suggest, a regression introduced in 1.0.2, see [#760](https://github.com/nodejs/io.js/issues/760).
* Calling `dns.setServers()` while a DNS query is in progress can cause the process to crash on a failed assertion. [#894](https://github.com/nodejs/io.js/issues/894)
* `url.resolve` may transfer the auth portion of the url when resolving between two full hosts, see [#1435](https://github.com/nodejs/io.js/issues/1435).
* [[`d1c27b2e29`](https://github.com/nodejs/node/commit/d1c27b2e29)] - **module**: fix module preloading when cwd is ENOENT (Bradley Meck) [#2353](https://github.com/nodejs/node/pull/2353)
* [[`5d7486941b`](https://github.com/nodejs/node/commit/5d7486941b)] - **repl**: filter integer keys from repl tab complete list (James M Snell) [#2409](https://github.com/nodejs/node/pull/2409)
* [[`7f02443a9a`](https://github.com/nodejs/node/commit/7f02443a9a)] - **repl**: dont throw ENOENT on NODE_REPL_HISTORY_FILE (Todd Kennedy) [#2451](https://github.com/nodejs/node/pull/2451)
* [[`56a2ae9cef`](https://github.com/nodejs/node/commit/56a2ae9cef)] - **src**: improve startup time (Evan Lucas) [#2483](https://github.com/nodejs/node/pull/2483)
* [[`14653c7429`](https://github.com/nodejs/node/commit/14653c7429)] - **stream**: rename poorly named function (Ben Noordhuis) [#2479](https://github.com/nodejs/node/pull/2479)
* [[`1c6e014bfa`](https://github.com/nodejs/node/commit/1c6e014bfa)] - **stream**: micro-optimize high water mark calculation (Ben Noordhuis) [#2479](https://github.com/nodejs/node/pull/2479)
* [[`536c3d0537`](https://github.com/nodejs/node/commit/536c3d0537)] - **test**: use reserved IP in test-net-connect-timeout (Rich Trott) [#2257](https://github.com/nodejs/node/pull/2257)
* [[`5df06fd8df`](https://github.com/nodejs/node/commit/5df06fd8df)] - **test**: add spaces after keywords (Brendan Ashworth)