deps: upgrade libuv to e89aced
test: re-enable simple/test-setproctitle on darwin

The functionality is available again per joyent/libuv@14eb8b0
and joyent/libuv@e89aced.

Fixes #3687.
crypto: fix base64 padding regression

Commit 9901b69c introduces a small regression where the trailing base64
padding is no longer written out when Cipher#final is called. Rectify
that.

Fixes #4837.
stream: Start out in sync=true state

The Readable and Writable classes will nextTick certain things
if in sync mode.  The sync flag gets unset after a call to _read
or _write.  However, most of these behaviors should also be
deferred until nextTick if no reads have been made (for example,
the automatic '_read up to hwm' behavior on Readable.push(chunk))

Set the sync flag to true in the constructor, so that it will not
trigger an immediate 'readable' event, call to _read, before the
user has had a chance to set a _read method implementation.
stream: Do not switch to objectMode implicitly

Only handle objects if explicitly told to do so in the options
object.  Non-buffer/string chunks are an error if not already in
objectMode.

Close #4662