vm: cleanup module memory leakage

There are some paths here that led to dangling contexts. By being smarter with
handle management we can get rid of all the cleanup code and fix those issues.

This is a backport of commit 7063575.
bench: add http_simple_auto benchmark

Starts a server and benchmarks it with ab.
bench: start a worker for each CPU
fs: no end emit after createReadStream.pause()

In case a fd option is given to fs.createReadStream a read will instantly
happen. But in the edge case where fd point to an empty file and .pause()
was executed instantly, the end event would emit since no async wait was
between fs.createReadStream and the file read there emits end.
deps: upgrade libuv to 2ec0986
stream: don't call `cleanup` twice on `end` and `close`
http: fix duplicated variable declaration
deps: cherry-pick libuv commit 4690204

libuv cannot be upgraded right now (API change in upstream libuv) but this
commit fixes a segmentation fault on SunOS systems, hence the cherry-pick.
upgrade npm to 1.1.23

This also upgrades node-gyp to 0.4.3
Revert "tests: kill process group on failure"

This reverts commit 0cebfc8ddb509fbf5f865bb660b73e96680b3f65.
2012.05.28, Version 0.7.9 (unstable)

* Upgrade V8 to 3.11.1

* Upgrade npm to 1.1.23

* uv: rework reference counting scheme (Ben Noordhuis)

* uv: add interface for joining external event loops (Bert Belder)

* repl, readline: Handle Ctrl+Z and SIGCONT better (Nathan Rajlich)

* fs: 64bit offsets for fs calls (Igor Zinkovsky)

* fs: add sync open flags 'rs' and 'rs+' (Kevin Bowman)

* windows: enable creating directory junctions with fs.symlink (Igor Zinkovsky, Bert Belder)

* windows: fix fs.lstat to properly detect symlinks. (Igor Zinkovsky)

* Fix #3270 Escape url.parse delims (isaacs)

* http: make http.get() accept a URL (Adam Malcontenti-Wilson)

* Cleanup vm module memory leakage (Marcel Laverdet)

* Optimize writing strings with Socket.write (Bert Belder)

* add support for CESU-8 and UTF-16LE encodings (koichik)

* path: add path.sep to get the path separator. (Yi, EungJun)

* net, http: add backlog parameter to .listen() (Erik Dubbelboer)

* debugger: support mirroring Date objects (Fedor Indutny)

* addon: add AtExit() function (Ben Noordhuis)

* net: signal localAddress bind failure in connect (Brian Schroeder)

* util: handle non-string return value in .inspect() (Alex Kocharin)
net: fix 'close' event emit order

The server 'close' event was emitted before the last client 'close' event. Not
exactly fatal but potentially confusing.

Before this commit the order looked something like [client, server, client],
now it looks like [client, client, server].

See #3340 for more details.
fs: no end emit after createReadStream.pause()

In case a fd option is given to fs.createReadStream a read will instantly
happen. But in the edge case where fd point to an empty file and .pause()
was executed instantly, the end event would emit since no async wait was
between fs.createReadStream and the file read there emits end.

This is a cherry-pick of commit 1f3e4a7 into the v0.6 branch.
deps: upgrade libuv to 7556590
Merge branch 'v0.7.9-release'
Now working on 0.7.10
test: update pummel/test-exec

ChildProcess.prototype._internal is called ChildProcess.prototype._handle now.
doc: remove all references to setsid

Fixes #2299.
uv: upgrade to 87dbffbd
child_process: new stdio API for .spawn() method