Before this commit it was declared static (in a header file!), meaning
it got duplicated in every file that includes it.

A few duplicated pointers is not the end of the world but it introduces
a lot of potential for confusion because root_cert_store in file A is
not the root_cert_store in file B.

Moral of the story: don't declare static variables in header files.

Doesn't matter now but it will if/when we have support for multiple
threads.

- The caveats no longer apply.
- Document options arguments, including `displayErrors` and the
  different things it means in each place.
- Re-did examples to be more on point, e.g. `runInContext` example
  runs multiple scripts in the same context.
- Documented how `vm.createContext`s meaning has substantially changed,
  and is now more of a "contextifier" than a "creator."
- Reordered vm functions to be readable in order; the concept of
  contextifying needs to come before `runInContext` and
  `runInNewContext`.
- Documented new `vm.isContext`.
- Documented the `vm.Script` constructor, instead of `createScript`,
  since factory methods are silly and we wanted to document the class's
  methods anyway.
- Documented `script.runInContext`.
- Change stability to stable, if I may be so bold.

Passing a filename is still supported in place of certain options
arguments, for backward-compatibility, but timeout and display-errors
are not translated since those were undocumented.

Also managed to eliminate an extra stack trace line by not calling
through the `createScript` export.

Added a few message tests to show how `displayErrors` works.

In `Timer.now` always update the loop time by calling uv_update_time.
Previously we were trying to cache the loop time to prevent extra
syscalls. While a noble goal, it can cause timers to fire early in
certain circumstances. Especially seen in cpu bound work loads or work
loads with synchronous file operations.

Conflicts:
	AUTHORS
	ChangeLog
	deps/uv/ChangeLog
	deps/uv/include/uv-darwin.h
	deps/uv/src/unix/darwin.c
	deps/uv/src/unix/fsevents.c
	deps/uv/src/version.c
	lib/_stream_writable.js
	src/node_version.h

This fixes the regression introduced by 54580791, which breaks the
net/net-pipe benchmark script.

Closes #6145

Make the crypto.randomBytes() and crypto.pbkdf2() callback functions
run inside the current domain (if any.)

Fixes #3965.

Previously, calling `vm.createContext(o)` repeatedly on the same `o`
would cause new C++ `ContextifyContext`s to be created and stored on
`o`, while the previous resident went off into leaked-memory limbo.
Now, repeatedly trying to contextify a sandbox will do nothing after
the first time.

To detect this, an independently-useful `vm.isContext(sandbox)` export
was added.

This is always something you should do when using `SetHiddenValue`,
apparently. Fixes #6115. Thanks @tjfontaine for the tips.

This was a remnant of the original Contextify code, wherein
ContextifyContext was a user-exposed object. In vm, it is not, so all
of the ObjectWrap and function-template stuff for the ContextifyContext
constructor is now unnecessary.

Closes #6087

Closes #6087

Closes #6090

There's no need to create a new Buffer instance if we're just going to
immediately call toString() at the end anyway.  Better to create a
string up front, and setEncoding() on the streams, and do a string
concatenation instead.

Only return strings when encoding is not null.

Since the encoding is no longer relevant once it is decoded to a Buffer,
it is confusing and incorrect to pass the encoding as 'utf8' or whatever
in those cases.

Closes #6119

Follows @isaacs's recommendations in joyent/node#5018. Includes some
updates to documentation but not examples.

Conflicts:
	lib/domain.js

Just do the best we can with whatever libuv gives us.

Also, document the semantics of `ctime` and the compatibility with
Windows.

De-globalize use_npn and use_sni, they're only used in GetFeatures().

Should make tracing with valgrind a little easier on the eye and
possibly help expose libuv handle lifecycle issues.

Ad-hoc duplicate of V8's --stack-size option.  Superfluous in other
words.  Remove it.

UV_HANDLE_FIELDS is a libuv implementation detail.  The ares_task_t
struct only uses the uv_loop_t* field so be explicit about that.

Length arguments passed to SlowBuffer were coerced to Int32, not Uint32,
so passing a negative number would throw the following:

node: ../src/smalloc.cc:244: void node::smalloc::Alloc(): Assertion `length <= kMaxLength' failed.
Aborted (core dumped)

That has been fixed by coercing to Uint32 and comparing the value
against kMaxLength.

Due to a lot of the util.is* checks there was much unnecessary overhead
for the most common use case of Buffer. Which is creating a new Buffer
instance for data from incoming I/O. NativeBuffer is a simple way to
bypass all the unneeded checks and simply hand back a Buffer instance
while setting the length.

src/node_os.cc doesn't export anything that's used elsewhere. Remove it.

On windows process exit codes can be greater than INT32_MAX. This used
to be not much of a problem - greater values would just come out
negative. However since ca9eb718 a negative result value indicates that
uv_spawn() has failed, so this is no longer acceptable.

Instead of doing all the domain handling in core, allow the domain to
set an error handler that'll take care of it all. This way the domain
error handling can be abstracted enough for any user to use it.

The `exit_code` argument for the `ProcessWrap::OnExit` callback changed
from int to int64_t.