lib: reintroduce v8 module

I introduced this module over a year ago in a pull request as the v8
module but it was quickly subsumed by the tracing module.

The tracing module was recently removed again and that is why this
commit introduces the v8 module again, including the new features it
picked up commits d23ac0e and f8076c4.

PR-URL: https://github.com/iojs/io.js/pull/131
Reviewed-By: Chris Dickinson <christopher.s.dickinson@gmail.com>
Reviewed-By: Christian Tellnes <christian@tellnes.no>
Reviewed-By: Thorsten Lorenz <thlorenz@gmx.de>
Reviewed-By: Trevor Norris <trev.norris@gmail.com>
doc: change write() after end() streams example

Currently there's an example using http.ServerResponse stream, which
has a known bug and will not throw an error while writing after end().
Changed to a writable stream from fs which behaves as expected.

Fixes https://github.com/joyent/node/issues/8814.

PR-URL: https://github.com/iojs/io.js/pull/155
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Brendan Ashworth <squirrelslikeacorns@gmail.com>