v8: work around String::WriteAscii segfault

See http://code.google.com/p/v8/issues/detail?id=2493 for details.
Once the patch lands in upstream V8, this commit can be reverted.
punycode: update to v1.2.0

This update adds support for RFC 3490 separators for improved
compatibility with web browsers.
http: fix duplicate var initialization

IncomingMessage function contained duplicate initialization
of this._pendings. Line with one of those expressions has been
removed.
buffer: floating point read/write improvements

Improvements:
* floating point operations are approx 4x's faster
* Now write quiet NaN's
* all read/write on floating point now done in C, so no more need for
  lib/buffer_ieee754.js
* float values have more accurate min/max value checks
* add additional benchmarks for buffers read/write
* created benchmark/_bench_timer.js which is a simple library that
  can be included into any benchmark and provides an intelligent tracker
  for sync and async tests
* add benchmarks for DataView set methods
* add checks and tests to make sure offset is greater than 0
buffer: improve read/write speed with assert

Improved assert check order of execution and added additional checks on
parameters to ensure no bad values make it through (e.g. negative offset
values).
stream: Properly handle large reads from push-streams

Problem 1: If stream.push() triggers a 'readable' event, and the user
calls `read(n)` with some n > the highWaterMark, then the push() will
return false (indicating that they should not push any more), but no
future 'readable' event is coming (because we're above the
highWaterMark).

Solution: return true from push() when needReadable is set.

Problem 2: A read(n) for n != 0, after the stream had encountered an
EOF, would not trigger the 'end' event if the EOF was pushed in
synchronously by the _read() function.

Solution: Check for ended in stream.read() and schedule an end event if
the length now equals 0.

Fix #4585
assert that require() has a truthy path
TypedArrays: Improve dataview perf without endian param

V8 seems to be particularly slow converting an undefined value to false
in BooleanValue.

Revert this when we upgrade to V8 3.17, or whenever the fix discussed
in http://code.google.com/p/v8/issues/detail?id=2487 lands in V8.
repl: fix how to module requiring in code comment

This module requiring style is old.
This API has been changed in Node 0.1.16 726865af.
lint: Prefer double-quotes over single
module: assert that require() is called with a string

as requested in #4577
test: add module-loading test with empty string
deps: upgrade libuv to 4ba03dd