child_process: do not keep list of sent sockets

Keeping list of all sockets that were sent to child process causes memory
leak and thus unacceptable (see #4587). However `server.close()` should
still work properly.

This commit introduces two options:

* child.send(socket, { track: true }) - will send socket and track its status.
  You should use it when you want `server.connections` to be a reliable
  number, and receive `close` event on sent sockets.
* child.send(socket) - will send socket without tracking it status. This
  performs much better, because of smaller number of RTT between master and
  child.

With both of these options `server.close()` will wait for all sent
sockets to get closed.
benchmark: Add resume() in static_http_server
Revert "child_process: do not keep list of sent sockets"

This reverts commit db5ee0b3decace9b5d80ee535ce53183aff02909.
child_process: do not keep list of sent sockets

Keeping list of all sockets that were sent to child process causes memory
leak and thus unacceptable (see #4587). However `server.close()` should
still work properly.

This commit introduces two options:

* child.send(socket, { track: true }) - will send socket and track its status.
  You should use it when you want to receive `close` event on sent sockets.
* child.send(socket) - will send socket without tracking it status. This
  performs much better, because of smaller number of RTT between master and
  child.

With both of these options `server.close()` will wait for all sent
sockets to get closed.
v8: add %p option to --logfile, expands to pid

Useful when you are profiling multiple instances of V8 concurrently.
Submitted upstream: http://code.google.com/p/v8/issues/detail?id=2503

Refs #4617.
cluster: make --prof work for workers

Profiling in clustered environments doesn't work out of the box.

By default, V8 writes the profile data of all processes to a single
v8.log.

Running that log file through a tick processor produces bogus numbers
because many events won't match up with the recorded memory mappings
and you end up with graphs where 80+% of ticks is unaccounted for.

Fixing the tick processor to deal with multi-process output is not very
useful because the processes may be running wildly disparate workloads.

That's why we fix up the command line arguments to include
a "--logfile=v8-%p.log" argument (where %p is expanded to the PID)
unless it already contains a --logfile argument.

Fixes #4617.
npm: Upgrade to 1.2.2