configure: add mips-float-abi (soft, hard) option
tls: fix setting NPN protocols

The NPN protocols was set on `require('tls')` or `global` object instead
of being a local property. This fact lead to strange persistence of NPN
protocols, and sometimes incorrect protocol selection (when no NPN
protocols were passed in client options).

fix #6168
contextify: dealloc only after global and sandbox

Functions created using: `vm.runInNewContext('(function() { })')` will
reference only `proxy_global_` object and not `sandbox_`. Thus in case,
where there're no references to sandbox (such as in example above),
`ContextifyContext` will be destroyed and use-after-free might happen.
doc: fix blog link in blog posts and README

Apparently Joyent decommissioned joyeur.com but at least they saved the
contents of the blog.  Update the links in the README and the nodejs.org
blog posts.

Hat tip to Eugen Pirogoff (@eugenpirogoff) for pointing it out.

Fixes #6224.
tls: don't push() incoming data when ondata is set

Otherwise the data ends up "on the wire" twice, and
switching between consuming the stream using `ondata`
vs. `read()` would yield duplicate data, which was bad.
http: don't pass the request options to Agent

The `options` that were being passed in before here are specific to a
single request, which kinda defeats the purpose of using an Agent in the
first place.

On a worse note, these `options` have not yet been "processed" by the
`http.ClientRequest` class, so if `port: null` is set (like it is as the
result of a `url.parse()` call), then they take preference over the
processed values since the agent's "options" get mixed in last in the
`createSocket()` function.

Fixes #6197.
Fixes #6199.
Closes #6231.
contextify: fix ContextifyContext leak

Apparently, context->Global() won't be destroyed if the context itself
isn't marked as weak and independent.

Also, the weakness flag should be cleared once the weak callback is
executed, otherwise we'll get crashes in Debug builds.

fix #6115 and #6201
doc: specify the format of the `ca` tls option
doc: fix typos in the tls `NPNProtocols` option
deps: update v8 to 3.20.17.7
doc: document reserved status of SIGUSR1

Fixes #1212.
net: add a port validation to `connect`

Fix "Assertion failed" when trying to connect to non-int ports:

    Assertion failed: (args[2]->Uint32Value()), function Connect,
    file ../src/tcp_wrap.cc, line 379.
    Abort trap: 6
src: initialize c-ares task list on env init

Don't forget to initialize the c-ares task tree head when creating a
new Environment.  Oversight from the multi-context work that landed
in commit 756b622.

Fixes #6244.
dns: fix c-ares error reporting regression

The test case from the previous commit exposed a regression in the way
that c-ares errors are reported to JS land.  Said regression was
introduced in commit 756b622 ("src: add multi-context support").

Fixes the following test failure:

    $ out/Release/node test/simple/test-dns-regress-6244
    util.js:675
      var errname = uv.errname(err);
                       ^
    Error: err >= 0
        at Object.exports._errnoException (util.js:675:20)
        at errnoException (dns.js:43:15)
        at Object.onresolve [as oncomplete] (dns.js:145:19)

lib/dns.js erroneously assumed that the error code was a libuv error
code when it's really a c-ares status code.  Libuv handles getaddrinfo()
style lookups (which is by far the most common type of lookup), that's
why this bug wasn't discovered earlier.
src: seed V8's random number generator at startup

The default entropy source is /dev/urandom on UNIX platforms, which is
okay but we can do better by seeding it from OpenSSL's entropy pool.

On Windows we can certainly do better; on that platform, V8 seeds the
random number generator using only the current system time.

Fixes #6250.
src: fix v8 PRNG entropy seeding

It was pointed out by a member of the V8 team that the call to
V8::SetEntropySource() should come before V8::Initialize().

See also commit 7ac2391.
deps: update v8 to 3.20.17.11

fix #6235
readline: handle input starting with control chars

Handle control characters only when there is a single byte in the
stream, otherwise fall through to the standard multibyte handling.
tls: wrap tls inside tls using legacy API

Allow wrapping TLSSocket inside another TLSSocket, emulate it using
SecurePair in legacy APIs.

fix #6204
Revert "deps: update v8 to 3.20.17.11"

After the upgrade from 3.20.17.7 to 3.20.17.11, we've begun hitting
random assertions in V8 in memory-constrained / GC-heavy situations.

The assertions all seem to be related to heap allocations and garbage
collection but apart from that, they're all over the place.

This reverts commit 970bdccc38fee27e10ff1a3b68f3fea3417788a1.