doc: Mention python dep in downloads page

Closes #3604
blog: v0.11.6
uv: Upgrade v0.10.14
2013.08.21, Version 0.10.17 (Stable)

* uv: Upgrade v0.10.14

* http_parser: Do not accept PUN/GEM methods as PUT/GET (Chris Dickinson)

* tls: fix assertion when ssl is destroyed at read (Fedor Indutny)

* stream: Throw on 'error' if listeners removed (isaacs)

* dgram: fix assertion on bad send() arguments (Ben Noordhuis)

* readline: pause stdin before turning off terminal raw mode (Daniel Chatfield)
Merge branch 'v0.10.17-release' into v0.10
Now working on 0.10.18
blog: Post for v0.10.17
tools: script to report [un]stable build
tools: script release steps after jenkins build
uv: update to v0.10.15
stream: Pass 'buffer' encoding to decoded writables

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
child_process: Callback with Buffers from exec

Only return strings when encoding is not null.
child_process: Avoid extra copy for string stdio

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.
stream: change default hwm for objectMode to 16
doc: mark repl as stable

Closes #6090
doc: Adjust util stability index to 'API Frozen'

Closes #6087
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.