http: Don't hot-path end() for large buffers

The benefits of the hot-path optimization below start to fall off when
the buffer size gets up near 128KB, because the cost of the copy is more
than the cost of the extra write() call.  Switch to the write/end method
at that point.

Heuristics and magic numbers are awful, but slow http responses are
worse.

Fix #4975
doc: don't mark fs callbacks as optional

Refs #5005, #5008
stream: Never call decoder.end() multiple times

Updated version that does what it says without assigning state.decoder.
test: No need for kicking in streams2 test

This was necessary when we weren't auto-starting when a 'readable'
listener is added.
stream: Return self from readable.wrap

Also, set paused=false *before* calling resume().  Otherwise,
there's an edge case where an immediately-emitted chunk might make
it call pause() again incorrectly.
v8: move 32 bit heap hint on sunos

Setting the V8 heap at or near 0x20000000 on 32bit sunos only allows
512 MB of heap space, instead on sunos move this to 0x80000000.

Fixes #4010.
install: don't install man page twice

Looks like a merge conflict in 77ed12f left in the old, unconditional
install rule. Remove it, the new and improved rule is a few lines down.

Fixes #5044.
deps: upgrade libuv to b45a74f
doc: https: Fix the link to tls.connect
doc: fix typo in crypto docs
node: revert removal of MakeCallback

In 0168109 an implementation of MakeCallback was accidently removed. It
has been re-added.
tls: write pending data of opposite side

Fix stucked CryptoStream behaviour, happening when one of the sides
locks-up in queued state.

fix #5023
doc: fix broken links in blog footer

The blog lives at blog.nodejs.org while the main website lives at
nodejs.org. Ergo, use absolute URLs for links to the main website.

Fixes #5062.