* Built-in debugger improvements.

* Add setsid, setuid, setgid options to child_process.spawn
  (Isaac Schlueter)

* tty module improvements.

* Upgrade libev to 4.3, libeio to latest, c-ares to 1.7.4

* Allow third party hooks before main module load.
  (See 496be457b6a2bc5b01ec13644b9c9783976159b2)

* Don't stat() on cached modules. (Felix Geisendörfer)