Closes GH-774.

http://codereview.chromium.org/6676019/

Closes GH-759.

Closes GH-768.

Change the natives to use this class instead of creating completely new
strings. Reduces memory usage by about 1 MB.

This ensures that the check_function_exists() for fdatasync in the
libeio CMakeLists.txt is not run, since that fails on some versions of
OSX (http://public.kitware.com/Bug/view.php?id=10044).

Test: Anders Conbere <aconbere@gmail.com>
Fix: Andreas Reich <andreas@reich.name>

Closes GH-431.
Closes GH-502.

This reverts commit f3d36412.

Landed in master instead.

Still broken.

BUG=v8:884

BUG=v8:884

Thanks to Matthew Woolman

This is to mirror the behavior introduced in
aa95e570.

Closes GH-727.

This does 3 things:

1. Delimiters and "unwise" characters are never included in the
   hostname or path.
2. url.format will sanitize string URLs that are passed to it.
3. The parsed url's 'href' member will be the sanitized url, which may
   not match the argument to url.parse.

Since "error" events will throw when unhandled anyhow, it makes no sense
to throw from an EventEmitter's method, especially for such a minor
misdemeanor as attempting to write to a non-writable stream.