doc: Adjust util stability index to 'API Frozen'

Closes #6087
vm: rip out ObjectWrap from ContextifyContext

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.
vm: use MakeWeak to fix leaking contexts

This is always something you should do when using `SetHiddenValue`,
apparently. Fixes #6115. Thanks @tjfontaine for the tips.
vm: add isContext; prevent double-contextifying

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.
crypto: make randomBytes/pbkdf2 cbs domain aware

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

Fixes #3965.
Merge remote-tracking branch 'ry/v0.10'

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
timer_wrap: Timer.now always update loop time

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.
pipe_wrap: squelch integer type conversion warning
vm: update API to use options argument

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.
vm: document vm2's changes.

- 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.
vm: Support legacy API as well

This adds support for programs that might currently do the
previous style such as vm.runInThisContext(code, filename, timeout, disp).
repl: Catch syntax errors better

Replace the growing list of 'isSyntaxError' whackamole conditions with a
smarter approach.  This creates a vm Script object *first*, which will
parse the code and raise a SyntaxError right away.

We still do need the test function, but only because strict mode syntax
errors are not recoverable, and should be raised right away.  Really, we
should probably *only* continue on "unexpected end of input" SyntaxErrors.

Also fixes a very difficult-to-test nit where the '...' indentation is
not properly cleared when you ^C out of a syntax error.

Closes #6093
repl: treat "Assignment to const" as syntax error

Adding a new `repl-harmony` test file here because adding the
`--use_strict --harmony` flags on the main repl test file was causing
lots of unrelated failures, due to global variable assignments and
things like that. This new test file is based off of the original
repl.js test file, but has a lot of the tests stripped out. A test case
for this commit is included though.

Fixes #6132.